Exposure apparatus, method for producing device, and method for controlling exposure apparatus

ABSTRACT

An exposure apparatus exposes a substrate by projecting an image of a pattern on the substrate via a projection optical system and a liquid. The exposure device has a liquid supply mechanism which supplies the liquid between the projection optical system and the substrate. The liquid feeding mechanism stops the supply of the liquid when abnormality is detected. This suppresses influence to devices and members in the periphery of the substrate caused by leakage of the liquid forming a liquid immersion area, thereby realizing satisfactory exposure processing.

CROSS-REFERENCE

This is a Division of U.S. patent application Ser. No. 11/338,661 filedJan. 25, 2006, which in turn is a Continuation of InternationalApplication No. PCT/JP2004/010991 filed Jul. 26, 2004 claiming theconventional priority of Japanese patent Applications No. 2003-281183filed on Jul. 28, 2003 and No. 2004-045104 filed on Feb. 20, 2004. Thedisclosures of these applications are incorporated herein by referencein their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an exposure apparatus for exposing asubstrate via a projection optical system and a liquid, a method forproducing a device based on the use of the exposure apparatus, and amethod for controlling the exposure apparatus.

2. Description of the Related Art

Semiconductor devices and liquid crystal display devices are produced bymeans of the so-called photolithography technique in which a patternformed on a mask is transferred onto a photosensitive substrate. Theexposure apparatus, which is used in the photolithography step, includesa mask stage for supporting the mask and a substrate stage forsupporting the substrate. The pattern on the mask is transferred ontothe substrate via a projection optical system while successively movingthe mask stage and the substrate stage. In recent years, it is demandedto realize the higher resolution of the projection optical system inorder to respond to the further advance of the higher integration of thedevice pattern. As the exposure wavelength to be used is shorter, theresolution of the projection optical system becomes higher. As thenumerical aperture of the projection optical system is larger, theresolution of the projection optical system becomes higher. Therefore,the exposure wavelength, which is used for the exposure apparatus, isshortened year by year, and the numerical aperture of the projectionoptical system is increased as well. The exposure wavelength, which isdominantly used at present, is 248 nm of the KrF excimer laser. However,the exposure wavelength of 193 nm of the ArF excimer laser, which isshorter than the above, is also practically used in some situations.When the exposure is performed, the depth of focus (DOF) is alsoimportant in the same manner as the resolution. The resolution R and thedepth of focus δ are represented by the following expressionsrespectively.R=k ₁ ·λ/NA  (1)δ=±k ₂ ·λ/NA ²  (2)

In the expressions, λ represents the exposure wavelength, NA representsthe numerical aperture of the projection optical system, and k₁ and k₂represent the process coefficients. According to the expressions (1) and(2), the following fact is appreciated. That is, when the exposurewavelength λ is shortened and the numerical aperture NA is increased inorder to enhance the resolution R, then the depth of focus δ isnarrowed.

If the depth of focus δ is too narrowed, it is difficult to match thesubstrate surface with respect to the image plane of the projectionoptical system. It is feared that the margin is insufficient during theexposure operation. Accordingly, the liquid immersion method has beensuggested, which is disclosed, for example, in International PublicationNo. 99/49504 as a method for substantially shortening the exposurewavelength and widening the depth of focus. In this liquid immersionmethod, the space between the lower surface of the projection opticalsystem and the substrate surface is filled with a liquid such as wateror any organic solvent to form a liquid immersion area so that theresolution is improved and the depth of focus is magnified about n timesby utilizing the fact that the wavelength of the exposure light beam inthe liquid is 1/n as compared with that in the air (n represents therefractive index of the liquid, which is about 1.2 to 1.6 in ordinarycases).

In the case of the liquid immersion exposure apparatus, if the liquidfor the exposure causes any leakage or any invasion, there is such apossibility that any inconvenience may be caused such that the apparatusand the members undergo, for example, the malfunction, the electricleakage, and the rust due to the liquid. Further, such a situation makesit impossible to perform the exposure process satisfactorily.

SUMMARY OF THE INVENTION

The present invention has been made taking the foregoing circumstancesinto consideration, an object of which is to provide an exposureapparatus, a method for producing a device, and a method for controllingthe exposure apparatus, in which the exposure process can be performedsatisfactorily even when the liquid immersion method is used. Anotherobject of the present invention is to provide an exposure apparatus, amethod for producing a device, and a method for controlling the exposureapparatus, in which the exposure process can be performed satisfactorilywhile suppressing the influence exerted by the leakage and the invasionof the liquid for the exposure.

In order to achieve the objects as described above, the presentinvention adopts the following constructions corresponding to FIGS. 1 to24 as illustrated in embodiments. However, parenthesized referencenumerals affixed to respective elements merely exemplify the elements byway of example, with which it is not intended to limit the respectiveelements.

According to a first aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternonto the substrate (P); and

a liquid supply mechanism (10) which supplies the liquid (1) to a spacebetween the projection optical system (PL) and the substrate (P),wherein:

the liquid supply mechanism (10) stops the supply of the liquid (1) whenany abnormality or trouble is detected.

According to the present invention, the supply of the liquid by theliquid supply mechanism is stopped when the abnormality is detected.Accordingly, it is possible to avoid the leakage and the invasion of theliquid, and it is possible to avoid the expansion of the damage causedthereby. Therefore, it is possible to avoid the occurrence of theinconvenience such as the malfunction and the rust of the peripheralunit and the member which would be otherwise caused by the liquid, andthe variation or fluctuation of the environment in which the substrateis placed. Further, it is possible to reduce the influence of theinconvenience as described above.

According to a second aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternthrough the liquid (1) onto the substrate (P); and

an electric unit (47, 48), wherein:

supply of electric power to the electric unit (47, 48) is stopped whenany abnormality is detected to avoid any electric leakage due toadhesion of the liquid (1).

According to the present invention, the supply of the electric power tothe electric unit is stopped to avoid the electric leakage which wouldbe otherwise caused by the adhesion of the liquid. Therefore, it ispossible to suppress the occurrence of the inconvenience including, forexample, the influence on the peripheral unit caused by the electricleakage and the malfunction of the electric unit itself. Further, it ispossible to reduce the damage caused thereby.

According to a third aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternthrough the liquid (1) onto the substrate (P); and

a suction port (42A, 66) which is communicated with a suction system(25), wherein:

suction through the suction port (42A, 66) is stopped when anyabnormality is detected to avoid any inflow of the liquid (1).

The exposure apparatus includes, for example, various suction portsincluding, for example, the suction port for the air bearing (gasbearing) for supporting the stage unit in a non-contact manner withrespect to the guide surface, and the suction port for the holder unitfor attracting and holding the mask and the substrate. If the liquidflows into such a suction port, the malfunction is caused in the vacuumsystem (suction system) such as the vacuum pump communicated with thesuction port. According to the present invention, the suction throughthe suction port is stopped when the abnormality is detected. Therefore,it is possible to avoid the inconvenience which would be otherwisecaused such that the liquid flows into the vacuum system via the suctionport. In the first to third aspects of the present invention, the phrase“abnormality is detected” means the fact that any situation, in whichthe exposure of the substrate through the liquid, i.e., the liquidimmersion exposure is harmfully affected, is detected. This concept alsoincludes the detection of not only the abnormality concerning the flowof the liquid but also the abnormality in relation to the operation ofthe stage which is movable while holding the substrate. Further, thisconcept also includes the detection of the abnormality in the relatedunit connected to the exposure apparatus. This concept also includessuch a case that the abnormal signal (alarm) is detected, for example,for the related unit of the liquid-producing unit for producing theliquid to be supplied to the exposure apparatus.

According to a fourth aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternthrough the liquid (1) onto the substrate (P);

a suction port (21, 61, 66) which is communicated with a suction system(25, 70, 74);

a separator (22, 71, 75) which separates gas from the liquid (1) suckedthrough the suction port (21, 61, 66); and

a drying unit (23, 72, 76) which dries the gas separated by theseparator (22, 71, 75).

For example, when the liquid is sucked through the liquid suction port(recovery port) of the liquid recovery mechanism by using the vacuumsystem, if the recovered liquid component flows into the vacuum system(suction system), then the malfunction of the vacuum system or the likeis caused. According to the present invention, the liquid and the gas,which are sucked through the suction port, are subjected to thegas/liquid separation by using the separator, and the gas separated bythe separator is further dried by using the drying unit. Accordingly, itis possible to avoid the inconvenience which would be otherwise causedsuch that the liquid component (including the wet gas) flows into thevacuum system. Therefore, the operation for recovering the liquid by theliquid recovery mechanism can be maintained satisfactorily for a longperiod of time while avoiding the occurrence of the inconvenience suchas the malfunction of the vacuum system (suction system) or the like. Itis possible to avoid the leakage of the liquid which would be otherwisecaused by the impossibility of the recovery operation to be performed bythe liquid recovery mechanism.

According to a fifth aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a substrate stage (PST) which is movable while holding the substrate (P)and which has a first area (LA1) thereon;

a projection optical system (PL) which projects an image of a patternonto the substrate (P), which includes an end portion (2 a) disposed onan image plane side, and which has a second area (LA2) which is opposedto the first area (LA1) to retain the liquid (1) between at least a partof the first area (LA1) and the second area (LA2); and

a control unit (CONT) which restricts movement of the substrate stage(PST) depending on positional relationship between the first area (LA1)and the second area (LA2).

According to the present invention, when the exposure apparatus isconstructed such that the liquid is retained between the first area andthe second area, it is possible to avoid the inconvenience such as theleakage of the liquid, for example, by restricting the movement of thesubstrate stage so as to avoid the positional relationship in which theliquid cannot be retained between the first area and the second area.

According to a sixth aspect of the present invention, there is providedan exposure apparatus (EX) which exposes a substrate (P) by radiating anexposure light beam (EL) onto the substrate (P) through a liquid (1),the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternthrough the liquid (1) onto the substrate (P);

a substrate stage (PST) which is movable while holding the substrate(P);

a base member (41) which movably supports the substrate stage (PST);

a first detector (80C) which is provided for the substrate stage (PST)and which detects the liquid (1);

a second detector (80D) which is provided for the base member (41) andwhich detects the liquid (1); and

a control unit (CONT) which controls operation of the exposure apparatusdepending on detection results of the first detector (80C) and thesecond detector (80D).

According to the present invention, the operation of the exposureapparatus is controlled depending on the detection results of the firstdetector and the second detector which are provided at the mutuallydifferent positions. Accordingly, it is possible to apply theappropriate treatment or countermeasure corresponding to the range ofdiffusion of the leaked liquid. Therefore, it is possible to shorten theperiod of time required for the restoring operation after the occurrenceof the leakage of the liquid, and it is possible to avoid the decreasein the working rate of the exposure apparatus. For example, when thefirst detector, which is provided for the substrate stage, detects thepresence of the liquid, the control unit judges that the range ofdiffusion of the leaked liquid is a relatively narrow range. The controlunit applies the appropriate treatment corresponding to the range, forexample, such that the supply of the liquid to be performed by theliquid supply mechanism is stopped. Accordingly, it is possible tosuppress the period of time required for the restoring operation to beminimum. On the other hand, when the second detector, which is providedfor the base member, detects the presence of the liquid, the controlunit judges that the range of diffusion of the leaked liquid resides ina relatively wide area. The control unit stops the supply of theelectric power to the electric unit represented, for example, by thedriving unit for driving the substrate stage. Accordingly, even when theleaked liquid is diffused in the wide range, it is possible to avoid theoccurrence of the damage such as the malfunction and the electricleakage of the electric unit.

According to a seventh aspect of the present invention, there isprovided an exposure apparatus (EX) which exposes a substrate (P) byradiating an exposure light beam (EL) onto the substrate (P) through aliquid (1), the exposure apparatus comprising:

a projection optical system (PL) which projects an image of a patternonto the substrate;

a liquid supply mechanism (10) which supplies the liquid (1) to a spacebetween the projection optical system (PL) and the substrate (P);

a substrate stage (PST) which is movable while holding the substrate(P); and

a control unit (CONT) which restricts a movement range of the substratestage (PST) to be a first range (SR1) during the supply of the liquid(1) by the liquid supply mechanism (10) and which restricts the movementrange of the substrate stage (PST) to be a second range (SR2) that iswider than the first range (SR1) during stop of the supply of the liquid(1) by the liquid supply mechanism (10).

According to the present invention, the movement range of the substratestage is restricted, for example, to the first range capable ofretaining the liquid on the substrate stage during the period in whichthe liquid supply mechanism supplies the liquid. Accordingly, it ispossible to avoid the inconvenience such as the leakage of the liquid orthe like. On the other hand, when the liquid supply mechanism stops thesupply of the liquid, the movement range of the substrate stage is thesecond range which is wider than the first range. Accordingly, it ispossible to smoothly perform the predetermined operation in relation tothe substrate stage, including, for example, the movement of thesubstrate stage to the substrate exchange position.

According to an eighth aspect of the present invention, there isprovided an exposure apparatus which exposes a substrate by radiating anexposure light beam onto the substrate through a liquid, the exposureapparatus comprising:

a projection optical system (PL) which projects an image of a patternonto the substrate;

a liquid supply mechanism (10) which supplies the liquid to an imageplane side of the projection optical system;

a stage (PST) which is movable on the image plane side of the projectionoptical system; and

a control unit (CONT) which controls a movement range of the stage,wherein:

the control unit restricts the movement range of the stage, which isadopted when the liquid is retained between the projection opticalsystem and the stage, to be narrower than that of the stage which isadopted when the liquid is not retained between the projection opticalsystem and the stage.

According to the eighth aspect of the present invention, the liquid canbe satisfactorily retained continuously between the projection opticalsystem and the stage, for example, during the exposure of the substrateon the stage. When the liquid is not retained between the projectionoptical system and the stage, it is possible to smoothly perform anotheroperation such as the substrate exchange.

According to a ninth aspect of the present invention, there is provideda method for producing a device, comprising using the exposure apparatus(EX) as defined in any one of the aspects described above. According tothe present invention, the driving of the predetermined unit is stoppedwhen the abnormality is detected. Therefore, it is possible to avoid theoccurrence of the inconvenience such as the malfunction of theapparatus, and it is possible to produce the device in a satisfactoryenvironment for the apparatus.

According to a tenth aspect of the present invention, there is provideda method for controlling an exposure apparatus (EX) which exposes asubstrate by radiating an exposure light beam onto the substrate througha liquid, the exposure apparatus being provided with componentsincluding a projection optical system (PL) which projects an image of apattern onto the substrate, a liquid supply mechanism (10) whichsupplies the liquid (1) to an image plane side of the projection opticalsystem, a unit (47, 48) which uses electric energy as driving force, anda unit (42, PH) which serves to suck gas, and the exposure apparatusbeing connected to an external related unit, the method for controllingthe exposure apparatus comprising:

supplying the liquid to the image plane side of the projection opticalsystem;

receiving a signal notifying any abnormality from at least one of thecomponents and the external related unit; and

restricting operation of at least one of the liquid supply mechanism(10), the unit (47, 48) which uses the electric energy as the drivingforce, and the unit (42, PH) which serves to suck the gas, on the basisof the signal.

According to the method for controlling the exposure apparatus of thepresent invention, when the abnormality arises in the exposure apparatusor in the related unit disposed outside the exposure apparatus, and theabnormality is the signal notifying such abnormality that the exposureof the substrate or the like is affected thereby, then the operation isrestricted for at least one of the liquid supply mechanism (10), theunit (47, 48) which uses the electric energy as the driving force, andthe unit (42, PH) which has the function to suck the gas. Accordingly,it is possible to avoid, for example, the liquid leakage, the electricleakage caused thereby, and the suction of the liquid by the suctionunit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic arrangement illustrating a first embodiment ofthe exposure apparatus of the present invention.

FIG. 2 shows a perspective view illustrating a substrate stage.

FIG. 3 shows a schematic arrangement illustrating those disposed in thevicinity of an end portion of a projection optical system, a liquidsupply mechanism, and a liquid recovery mechanism.

FIG. 4 shows a plan view illustrating a positional relationship among aprojection area of the projection optical system, the liquid supplymechanism, and the liquid recovery mechanism.

FIG. 5 schematically shows a sectional view illustrating a recovery unitprovided for a substrate stage.

FIG. 6 schematically illustrates a detector provided with an opticalfiber concerning a second embodiment of the exposure apparatus of thepresent invention.

FIG. 7 schematically illustrates a detector provided with an opticalfiber according to the second embodiment of the exposure apparatus ofthe present invention.

FIG. 8 shows a side view illustrating an exemplary arrangement of thedetector provided with the optical fiber.

FIG. 9 shows a plan view illustrating the arrangement shown in FIG. 8.

FIG. 10 shows a side view illustrating another exemplary arrangement ofthe detector provided with the optical fiber.

FIG. 11 shows a plan view illustrating another embodiment of a detectorprovided with the optical fiber.

FIG. 12 shows a perspective view illustrating another exemplaryarrangement of a detector provided with the optical fiber.

FIG. 13 schematically shows another embodiment of a detector providedwith the optical fiber.

FIG. 14 schematically illustrates a detector provided with a prismaccording to a third embodiment of the exposure apparatus of the presentinvention.

FIG. 15 schematically illustrates the detector provided with the prismaccording to the third embodiment of the exposure apparatus of thepresent invention.

FIG. 16 shows a plan view illustrating an exemplary arrangement of thedetector provided with the prism.

FIG. 17 shows another exemplary use of the detector provided with theprism.

FIG. 18 schematically shows another exemplary arrangement of thedetector provided with the prism.

FIGS. 19A and 19B show another embodiment of the detector provided withthe optical fiber.

FIGS. 20A and 20B illustrate another embodiment of the presentinvention.

FIGS. 21A and 21B illustrate another embodiment of the presentinvention.

FIG. 22 shows a flow chart illustrating exemplary steps of producing asemiconductor device.

FIG. 23 shows a block diagram illustrating the relationship ofconnection between a control unit and various units disposed inside theexposure apparatus and related units disposed outside the exposureapparatus to be controlled by the control unit on the basis of thedetection signals supplied from various detectors of the exposureapparatus according to the present invention.

FIG. 24 shows a flow chart illustrating the control contents of thecontrol unit of the exposure apparatus according to the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

An explanation will be made below about embodiments of the exposureapparatus of the present invention. However, the present invention isnot limited thereto.

FIG. 1 shows a schematic arrangement illustrating a first embodiment ofthe exposure apparatus of the present invention. With reference to FIG.1, an exposure apparatus EX includes a mask stage MST which supports amask M, a substrate stage PST which supports a substrate P, anillumination optical system IL which illuminates, with an exposure lightbeam EL, the mask M supported by the mask stage MST, a projectionoptical system PL which performs projection exposure for the substrate Psupported by the substrate stage PST with an image of a pattern of themask M illuminated with the exposure light beam EL, and a control unitCONT which collectively controls the overall operation of the exposureapparatus EX. An alarm unit K, which generates an alarm when anyabnormality arises in relation to the exposure process, is connected tothe control unit CONT. The exposure apparatus EX further includes a maincolumn 3 which supports the mask stage MST and the projection opticalsystem PL. The main column 3 is installed on a base plate 4 which isplaced horizontally on the floor surface. The main column 3 is formedwith an upper step 3A and a lower step 3B which protrude inwardly. Asshown in FIG. 23, the control unit is connected to the variouscomponents for constructing the exposure apparatus and the related unitsdisposed outside the exposure apparatus. The contents of the control ofthe control unit will be described later on.

The exposure apparatus EX of this embodiment is a liquid immersionexposure apparatus to which the liquid immersion method is applied inorder that the exposure wavelength is substantially shortened to improvethe resolution and the depth of focus is substantially widened. Theexposure apparatus EX includes a liquid supply mechanism 10 whichsupplies the liquid 1 onto the substrate P, and a liquid recoverymechanism 20 which recovers the liquid 1 from the substrate P. Theexposure apparatus EX forms a liquid immersion area AR2 on a part of thesubstrate P including a projection area AR1 of the projection opticalsystem PL by the liquid 1 supplied from the liquid supply mechanism 10at least during the period in which the pattern image of the mask M istransferred onto the substrate P. Specifically, the exposure apparatusEX is operated as follows. That is, the space between the surface of thesubstrate P and the optical element 2 disposed at the end portion(terminal end portion) of the projection optical system PL is filledwith the liquid 1. The pattern image of the mask M is projected onto thesubstrate P to expose the substrate P therewith via the projectionoptical system PL and the liquid 1 disposed between the projectionoptical system PL and the substrate P.

The embodiment of the present invention will be explained as exemplifiedby a case using the scanning type exposure apparatus (so-called scanningstepper) as the exposure apparatus EX in which the substrate P isexposed with the pattern formed on the mask M while synchronously movingthe mask M and the substrate P in mutually different directions(opposite directions) in the scanning directions. In the followingexplanation, the Z axis direction is the direction which is coincidentwith the optical axis AX of the projection optical system PL, the X axisdirection is the synchronous movement direction (scanning direction) forthe mask M and the substrate P in the plane perpendicular to the Z axisdirection, and the Y axis direction is the direction (non-scanningdirection) perpendicular to the Z axis direction and the Y axisdirection. The directions of rotation (inclination) about the X axis,the Y axis, and the Z axis are designated as θX, θY, and θZ directionsrespectively. The term “substrate” referred to herein includes thoseobtained by coating a semiconductor wafer surface with a photoresist asa photosensitive material, and the term “mask” includes a reticle formedwith a device pattern to be subjected to the reduction projection ontothe substrate.

The illumination optical system IL is supported by a support column 5which is fixed to the upper portion of the main column 3. Theillumination optical system IL is used so that the mask M, which issupported on the mask stage MST, is illuminated with the exposure lightbeam EL. The illumination optical system IL includes, for example, anexposure light source, an optical integrator which uniformizes theilluminance of the light flux radiated from the exposure light source, acondenser lens which collects the exposure light beam EL emitted fromthe optical integrator, a relay lens system, and a variable fielddiaphragm which sets the illumination area on the mask M illuminatedwith the exposure light beam EL to be slit-shaped. The predeterminedillumination area on the mask M is illuminated with the exposure lightbeam EL having a uniform illuminance distribution by the illuminationoptical system IL. Those usable as the exposure light beam EL radiatedfrom the illumination optical system IL include, for example, emissionlines (g-ray, h-ray, i-ray) in the ultraviolet region radiated, forexample, from a mercury lamp, far ultraviolet light beams (DUV lightbeams) such as the KrF excimer laser beam (wavelength: 248 nm), andvacuum ultraviolet light beams (VUV light beams) such as the ArF excimerlaser beam (wavelength: 193 nm) and the F₂ laser beam (wavelength: 157nm). In this embodiment, the ArF excimer laser beam is used.

In this embodiment, pure water is used for the liquid 1. Those capableof being transmitted through pure water include the ArF excimer laserbeam as well as the emission line (g-ray, h-ray, i-ray) in theultraviolet region radiated, for example, from a mercury lamp and thefar ultraviolet light beam (DUV light beam) such as the KrF excimerlaser beam (wavelength: 248 nm).

The mask stage supports the mask M. The mask stage MST has an opening34A which is provided at a central portion of the mask stage forallowing the pattern image of the mask M to pass therethrough. A masksurface plate 31 is supported on the upper step 3A of the main column 3by the aid of an anti-vibration unit 6. An opening 34B, which allows thepattern image of the mask M to pass therethrough, is also formed at acentral portion of the mask surface plate 31. A plurality of gasbearings (air bearings) 32, which are non-contact bearings, are providedon the lower surface of the mask stage MST. The mask stage MST issupported in a non-contact manner with respect to an upper surface(guide surface) 31A of the mask surface plate 31 by the aid of the airbearings 32. The mask stage MST is two-dimensionally movable in theplane perpendicular to the optical axis AX of the projection opticalsystem PL, i.e., in the XY plane, and it is finely rotatable in the θZdirection by the aid of a mask stage-driving mechanism such as a linearmotor. A movement mirror 35, which is movable with respect to theprojection optical system PL together with the mask stage MST, isprovided on the mask stage MST. A laser interferometer 36 is provided ata position opposed to the movement mirror 35. The position in thetwo-dimensional direction and the angle of rotation in the θZ direction(including the angles of rotation in the θX and θY directions in somecases) of the mask M on the mask stage MST are measured in real-time bythe laser interferometer 36. The result of the measurement is outputtedto the control unit CONT. The control unit CONT drives the maskstage-driving unit on the basis of the result of the measurementobtained by the laser interferometer 36 to thereby control the positionof the mask M supported on the mask stage MST.

The projection optical system PL projects the pattern on the mask M ontothe substrate P at a predetermined projection magnification β to performthe exposure. The projection optical system PL includes a plurality ofoptical elements including the optical element (lens) 2 provided at theend portion on the side of the substrate P. The optical elements aresupported by a barrel PK. In this embodiment, the projection opticalsystem PL is based on the reduction system having the projectionmagnification β which is, for example, ¼ or ⅕. The projection opticalsystem PL may be any one of the 1× magnification system and themagnifying system. A flange portion FLG is provided on the outercircumference of the barrel PK. A barrel surface plate 8 is supported onthe lower step 3B of the main column 3 by the aid of an anti-vibrationunit 7. The flange portion FLG of the projection optical system PL isengaged with the barrel surface plate 8, and thus the projection opticalsystem PL is supported by the barrel surface plate 8.

The optical element 2, which is disposed at the end portion of theprojection optical system PL of this embodiment, is provided detachably(exchangeably) with respect to the barrel PK. The liquid 1 in the liquidimmersion area AR2 makes contact with the optical element 2. The opticalelement 2 is formed of fluorite. Fluorite has a high affinity for water.Therefore, the liquid 1 is successfully allowed to make tight contactwith substantially the entire surface of the liquid contact surface 2 aof the optical element 2. That is, in this embodiment, the liquid(water) 1, which has the high affinity for the liquid contact surface 2a of the optical element 2, is supplied. Therefore, the highly tightcontact is effected between the liquid 1 and the liquid contact surface2 a of the optical element 2. The optical path between the opticalelement 2 and the substrate P can be reliably filled with the liquid 1.The optical element 2 may be formed of quartz having a high affinity forwater. A water-attracting (lyophilic or liquid-attracting) treatment maybe applied to the liquid contact surface 2 a of the optical element 2 tofurther enhance the affinity for the liquid 1.

A plate member 2P is provided to surround the optical element 2. Thesurface (i.e., the lower surface) of the plate member 2P opposed to thesubstrate P is a flat surface. The lower surface (liquid contactsurface) 2 a of the optical element 2 is also a flat surface. The lowersurface of the plate member 2P is substantially flush with the lowersurface of the optical element 2. Accordingly, the liquid immersion areaAR2 can be satisfactorily formed in a wide range. A surface treatment(lyophilic or liquid-attracting treatment) can be applied to the lowersurface of the plate member 2P in the same manner as the optical element2.

The substrate stage (movable member) PST is provided movably whileattracting and holding the substrate P by the aid of a substrate holder(substrate-retaining member) PH. A plurality of gas bearings (airbearings) 42, which are non-contact bearings, are provided on the lowersurface of the substrate stage. A substrate surface plate 41 issupported on the base plate 4 by the aid of an anti-vibration unit 9.The air bearings 42 are provided with discharge ports 42B for allowingthe gas (air) to blow against the upper surface (guide surface) 41A ofthe substrate surface plate 41, and suction ports 42A for sucking thegas from the space between the guide surface 41A and the lower surface(bearing surface) of the substrate stage PST. A constant gap ismaintained between the lower surface of the substrate stage PST and theguide surface 41A in accordance with the balance between the repulsiveforce based on the blow of the gas from the discharge ports 42B and theattracting force exerted by the suction ports 42A. That is, thesubstrate stage PST is supported in a non-contact manner with respect tothe upper surface (guide surface) 41A of the substrate surface plate(base member) 41 by the aid of the air bearings 42. The substrate stagePST is two-dimensionally movable in the plane perpendicular to theoptical axis AX of the projection optical system PL, i.e., in the XYplane, and it is finely rotatable in the θZ direction by the aid of asubstrate stage-driving mechanism such as a linear motor. Further, thesubstrate holder PH is provided movably in the Z axis direction, the θXdirection, and the θY direction as well. The substrate stage-drivingmechanism is controlled by the control unit CONT. That is, the substrateholder PH controls the focus position (Z position) and the angle ofinclination of the substrate P so that the surface of the substrate P isadjusted to match the image plane of the projection optical system PL inthe auto-focus manner and the auto-leveling manner. Further, thesubstrate holder PH positions the substrate P in the X axis directionand the Y axis direction.

A movement mirror 45, which is movable together with the substrate stagePST with respect to the projection optical system PL, is provided on thesubstrate stage PST (substrate holder PH). A laser interferometer 46 isprovided at a position opposed to the movement mirror 45. The angle ofrotation and the position in the two-dimensional direction of thesubstrate P on the substrate stage PST are measured in real-time by thelaser interferometer 46. The result of the measurement is outputted tothe control unit CONT. The control unit CONT drives the substratestage-driving mechanism including the linear motor on the basis of theresult of the measurement performed by the laser interferometer 46 tothereby position the substrate P supported on the substrate stage PST.

An auxiliary plate 43 is provided on the substrate stage PST (substrateholder PH) so that the substrate P is surrounded thereby (see FIG. 2).The auxiliary plate 43 has a flat surface which has approximately thesame height as that of the surface of the substrate P held by thesubstrate holder PH. Even when the edge area of the substrate P issubjected to the exposure, the liquid 1 can be retained under theprojection optical system PL by the aid of the auxiliary plate 43.

A recovery port (suction port) 61 of a recovery unit 60, which recoversthe liquid 1 flown to the outside of the substrate P, is providedoutside of the auxiliary plate 43 of the substrate holder PH. Therecovery port 61 is an annular groove formed to surround the auxiliaryplate 43. A liquid-absorbing member 62, which is formed of, for example,a sponge-like member or a porous member, is arranged therein.

FIG. 2 shows a schematic perspective view illustrating the substratestage PST and the substrate stage-driving mechanism for driving thesubstrate stage PST. With reference to FIG. 2, the substrate stage PSTis supported movably in the X axis direction by an X guide stage 44. Thesubstrate stage PST is movable by a predetermined stroke in the X axisdirection by an X linear motor 47 while being guided by the X guidestage 44. The X linear motor 47 includes a stator 47A which is providedto extend in the X axis direction for the X guide stage 44, and a mover47B which is provided corresponding to the stator 47A and which is fixedto the substrate stage PST. The mover 47B is driven with respect to thestator 47A, and thus the substrate stage PST is moved in the X axisdirection. In this arrangement, the substrate stage PST is supported ina non-contact manner by a magnetic guide including a magnet and anactuator to maintain a predetermined amount of gap in the Z axisdirection with respect to the X guide stage 44. The substrate stage PSTis moved in the X axis direction by the X linear motor 47 in a state ofbeing supported in a non-contact manner by the X guide stage 44.

A pair of Y linear motors 48, which are capable of moving the X guidestage 44 in the Y axis direction together with the substrate stage PST,are provided at the both ends of the X guide stage 44 in thelongitudinal direction. Each of the Y linear motors 48 includes a mover48B which is provided at each of the both ends of the X guide stage 44in the longitudinal direction, and a stator 48A which is providedcorresponding to the mover 48B. The movers 48B are driven with respectto the stators 48A, and thus the X guide stage 44 is moved in the Y axisdirection together with the substrate stage PST. The X guide stage 44 iscapable of effecting the rotational movement in the θZ direction as wellby adjusting the driving of the Y linear motors 48 respectively.Therefore, the Y linear motors 48 make it possible for the substratestage PST to move in the Y axis direction and in the θZ directionsubstantially integrally with the X guide stage 44.

A guide portion 49, which is formed to be L-shaped as viewed in a frontview and which guides the movement of the X guide stage 44 in the Y axisdirection, is provided on each of the both sides of the substratesurface plate 41 in the X axis direction. The guide portions 49 aresupported on the base plate 4 (FIG. 1). In this embodiment, the stator48A of the Y linear motor 48 is provided on a flat portion 49B of theguide portion 49. On the other hand, a recessed guide objective member50 is provided on each of the both ends of the lower surface of the Xguide stage 44 in the longitudinal direction. The guide portion 49 isprovided to make engagement with the guide objective member 50, and theupper surface (guide surface) 49A of the guide portion 49 is opposed tothe inner surface of the guide objective member 50. A gas bearing (airbearing) 51, which is a non-contact bearing, is provided for the guidesurface 49A of the guide portion 49. The X guide stage 44 is supportedin a non-contact manner with respect to the guide surfaces 49A.

A gas bearing (air bearing) 52, which is a non-contact bearing, isallowed to intervene between the stator 48A of the Y linear motor 48 andthe flat portion 49B of the guide portion 49. The stator 48A issupported in a non-contact manner with respect to the flat portion 49Bof the guide portion 49 by the air bearing 52. Therefore, the stators48A are moved in the −Y direction (+Y direction) in accordance with themovement of the X guide stage 44 and the substrate stage PST in the +Ydirection (−Y direction) according to the law of conservation ofmomentum. The movement of the stator 48A offsets the reaction forcecaused by the X guide stage 44 and the substrate stage PST, and it ispossible to avoid the change of the position of the center of gravity.That is, the stator 48A has a function to serve as the so-called countermass.

FIG. 3 shows a magnified view illustrating those disposed in thevicinity of the liquid supply mechanism 10, the liquid recoverymechanism 20, and the end portion of the projection optical system PL.The liquid supply mechanism 10 supplies the liquid 1 to the spacebetween the projection optical system PL and the substrate P. The liquidsupply mechanism 10 includes a liquid supply unit 11 which is capable offeeding the liquid 1, and supply nozzles 14 which are connected to theliquid supply unit 11 via a supply tube 15 and which supply, onto thesubstrate P, the liquid 1 fed from the liquid supply unit 11. The supplynozzles 14 are arranged closely to the surface of the substrate P. Theliquid supply unit 11 includes, for example, a tank for accommodatingthe liquid 1, and a pressurizing pump. The liquid supply unit 11supplies the liquid 1 onto the substrate P through the supply tube 15and the supply nozzles 14. The operation of the liquid supply unit 11 tosupply the liquid is controlled by the control unit CONT. The controlunit CONT is capable of controlling the liquid supply amount per unittime to be supplied onto the substrate P by the liquid supply unit 11.

A flow meter 12, which measures the amount of the liquid 1 to besupplied from the liquid supply unit 11 onto the substrate P (liquidsupply amount per unit time), is provided at an intermediate position ofthe supply tube 15. The flow meter 12 always monitors the amount of theliquid 1 to be supplied onto the substrate P, and the result of themeasurement is outputted to the control unit CONT. A valve 13, whichopens/closes the flow passage of the supply tube 15, is provided at anintermediate position of the supply tube 15 between the flow meter 12and the supply nozzle 14. The opening/closing operation of the valve 13is controlled by the control unit CONT. In this embodiment, the valve 13is based on the so-called normally off system in which the flow passageof the supply tube 15 is mechanically closed, for example, when thedriving source (power source) of the exposure apparatus EX (control unitCONT) is stopped, for example, due to any power failure.

The liquid recovery mechanism 20 recovers, from the surface of thesubstrate P, the liquid 1 supplied by the liquid supply mechanism 10.The liquid recovery mechanism 20 includes recovery nozzles (suctionports) 21 which are arranged closely to the surface of the substrate P,and a vacuum system (suction system) 25 which is connected to therecovery nozzles 21 via a recovery tube 24. The vacuum system 25 isconstructed to include a vacuum pump. The operation of the vacuum system25 is controlled by the control unit CONT. When the vacuum system 25 isdriven, the liquid 1 on the substrate P is recovered together with thesurrounding gas (air) through the recovery nozzles 21. A vacuum systemof a factory in which the exposure apparatus EX is arranged may be usedas the vacuum system 25 instead of providing the vacuum pump for theexposure apparatus.

A gas/liquid separator 22, which separates the gas from the liquid 1sucked through the recovery nozzles 21, is provided at an intermediateposition of the recovery tube 24. In this embodiment, as describedabove, the surrounding gas is also recovered through the recoverynozzles 21 together with the liquid 1 on the substrate P. The gas/liquidseparator 22 separates the gas from the liquid 1 recovered through therecovery nozzles 21. Those adoptable as the gas/liquid separator 22include, for example, an apparatus based on the gravity separationsystem in which the recovered liquid and the gas are allowed to flowthrough a tube member having a plurality of holes and the liquid isallowed to fall through the holes in accordance with the gravity actionto thereby separate the liquid and the gas from each other, and anapparatus based on the centrifugation system in which the recoveredliquid and the gas are separated from each other by using thecentrifugal force. The vacuum system 25 sucks the gas separated by thegas/liquid separator 22.

A drying unit 23, which dries the gas separated by the gas/liquidseparator 22, is provided between the vacuum system 25 and thegas/liquid separator 22. If the gas separated by the gas/liquidseparator 22 is mixed with any liquid component, then the gas is driedby the drying unit 23, and the dried gas is allowed to flow into thevacuum system 25. Accordingly, it is possible to avoid the occurrence ofthe inconvenience such as the malfunction of the vacuum system 25 whichwould be otherwise caused by the inflow of the liquid component. Thoseadoptable as the drying unit 23 include, for example, an apparatus suchas a cooling unit which is based on such a system that the gas (gasmixed with the liquid component) supplied from the gas/liquid separator22 is cooled to a temperature of not more than the dew point of theliquid to remove the liquid component thereby, and an apparatus such asa heater which is based on such a system that the gas is heated to atemperature of not less than the boiling point of the liquid to removethe liquid component thereby.

On the other hand, the liquid 1 separated by the gas/liquid separator 22is recovered by a liquid recovery unit 28 through a second recovery tube26. The liquid recovery unit 28 includes, for example, a tank foraccommodating the recovered liquid 1. For example, the liquid 1, whichis recovered by the liquid recovery unit 28, is discarded.Alternatively, the liquid 1 is cleaned and returned, for example, to theliquid supply unit 11 to reuse the liquid 1. A flow meter 27, whichmeasures the amount of the recovered liquid 1 (liquid recovery amountper unit time), is provided at an intermediate position of the secondrecovery tube 26 between the gas/liquid separator 22 and the liquidrecovery unit 28. The flow meter 27 always monitors the amount of theliquid 1 recovered from the surface of the substrate P, and the resultof the measurement is outputted to the control unit CONT. As describedabove, the surrounding gas is also recovered through the recoverynozzles 21 together with the liquid 1 on the substrate P. However, theliquid 1 and the gas are separated from each other by the gas/liquidseparator 22, and only the liquid component is fed to the flow meter 27.Accordingly, the flow meter 27 can correctly measure the amount of theliquid 1 recovered from the surface of the substrate P.

The exposure apparatus EX is provided with a focus-detecting system 56which detects the position of the surface of the substrate P supportedby the substrate stage PST. The focus-detecting system 56 includes alight-emitting section 56A which projects a detecting light flux from anobliquely upward position via the liquid 1 onto the substrate P, and alight-receiving section 56B which receives the reflected light beam ofthe detecting light flux reflected by the substrate P. Thelight-receiving result of the focus-detecting system 56 (light-receivingsection 56B) is outputted to the control unit CONT. The control unitCONT can detect the position information about the surface of thesubstrate P in the Z axis direction on the basis of the result of thedetection performed by the focus-detecting system 56. When a pluralityof detecting light fluxes are radiated from the light-emitting section56A, it is possible to detect the information about the inclination ofthe substrate P in the θX direction and the θY direction.

The focus-detecting system 56 is not limited to the detection of thesubstrate P, and can also detect the information about the surfaceposition of any object arranged on the image plane side of theprojection optical system PL. The focus-detecting system 56 detects theinformation about the surface position of the object (substrate P) viathe liquid 1. However, it is also possible to adopt a focus-detectingsystem which detects the information about the surface position of theobject (substrate P) not via the liquid 1 at the outside of the liquidimmersion area AR2.

As shown in the partial sectional view in FIG. 1, the liquid supplymechanism 10 and the liquid recovery mechanism 20 are supportedseparately by the barrel surface plate 8. Accordingly, the vibration,which is generated in the liquid supply mechanism 10 and the liquidrecovery mechanism 20, is not transmitted to the projection opticalsystem PL via the barrel surface plate 8.

FIG. 4 shows a plan view illustrating the positional relationship amongthe liquid supply mechanism 10, the liquid recovery mechanism 20, andthe projection area AR1 of the projection optical system PL. Theprojection area AR1 of the projection optical system PL has arectangular shape (slit-shaped form) which is long in the Y axisdirection. Three supply nozzles 14A to 14C are arranged on the +X side,and two recovery nozzles 21A, 21B are arranged on the −X side tointerpose the projection area AR1 in the X axis direction. The supplynozzles 14A to 14C are connected to the liquid supply unit 11 via thesupply tube 15, and the recovery nozzles 21A, 21B are connected to thevacuum system 25 via the recovery tube 24. The supply nozzles 14A′ to14C′ and the recovery nozzles 21A′, 21B′ are arranged at the positionsobtained by rotating those of the supply nozzles 14A to 14C and therecovery nozzles 21A, 21B by approximately 180°. The supply nozzles 14Ato 14C and the recovery nozzles 21A′, 21B′ are arranged alternately inthe Y axis direction. The supply nozzles 14A′ to 14C′ and the recoverynozzles 21A, 21B are arranged alternately in the Y axis direction. Thesupply nozzles 14A′ to 14C′ are connected to the liquid supply unit 11via the supply tube 15′. The recovery nozzles 21A′, 21B′ are connectedto the vacuum system 25 via the recovery tube 24′. A flow meter 12′ anda valve 13′ are provided at intermediate positions of the supply tube15′ in the same manner as in the supply tube 15. A gas/liquid separator22′ and a drying unit 23′ are provided at intermediate positions of therecovery tube 24′ in the same manner as in the recovery tube 24.

FIG. 5 shows the recovery unit 60 which recovers the liquid 1 outflowedto the outside of the substrate P. With reference to FIG. 5, therecovery unit 60 includes a recovery port (suction port) 61 which isformed annularly to surround the auxiliary plate 43 on the substrateholder PH, and a liquid-absorbing member 62 which is arranged in therecovery port 61 and which is formed of a sponge-like member or a porousmember such as porous ceramics. The liquid-absorbing member 62 is anannular member having a predetermined width, which is capable ofretaining a predetermined amount of the liquid 1. A flow passage 63,which is communicated with the recovery port 61, is formed in thesubstrate holder PH. The liquid-absorbing member 62, which is arrangedin the recovery port 61, has the bottom which makes contact with theflow passage 63. A plurality of liquid recovery holes 64 are providedbetween the auxiliary plate 43 and the substrate P on the substrateholder PH. The liquid recovery holes 64 are also connected to the flowpassage 63.

A plurality of projections 65, which are formed to support the backsurface of the substrate P, are provided on the upper surface of thesubstrate holder (substrate-holding member) PH for holding the substrateP. Each of the projections 65 is provided with an attracting hole 66 forattracting and holding the substrate P. The respective attracting holes66 are connected to a tube passage 67 formed in the substrate holder PH.

The flow passage 63, which is connected to the recovery port 61 and theliquid recovery holes 64 respectively, is connected to one end of a tubepassage 68 which is provided outside the substrate holder PH. On theother hand, the other end of the tube passage 68 is connected to avacuum system 70 including a vacuum pump. A gas/liquid separator 71 isprovided at an intermediate position of the tube passage 68. A dryingunit 72 is provided between the gas/liquid separator 71 and the vacuumsystem 70. When the vacuum system 70 is driven, the liquid 1 isrecovered from the recovery port 61 together with the surrounding gas.Even when the liquid 1 makes invasion from any gap between the substrateP and the auxiliary plate 43, and the liquid 1 enters the back surfaceside of the substrate P, then the liquid is recovered from the recoveryport 64 together with the surrounding gas. The gas, which is separatedby the gas/liquid separator 71 and which is dried by the drying unit 72,flows into the vacuum system 70. On the other hand, the liquid 1, whichis separated by the gas/liquid separator 71, flows into a liquidrecovery unit 73 which is provided with a tank or the like capable ofaccommodating the liquid 1. For example, the liquid 1, which isrecovered by the liquid recovery unit 73, is discarded. Alternatively,the liquid 1 is cleaned and returned, for example, to the liquid supplyunit 11 to reuse the liquid 1.

The tube passage 67, which is connected to the attracting holes 66, isconnected to one end of a tube passage 69 provided outside the substrateholder PH. On the other hand, the other end of the tube passage 69 isconnected to a vacuum system 74 including a vacuum pump provided outsidethe substrate holder PH. When the vacuum system 74 is driven, thesubstrate P, which is supported by the projections 65, is attracted andheld by the attracting holes 66. A gas/liquid separator 75 is providedat an intermediate position of the tube passage 69. A drying unit 76 isprovided between the gas/liquid separator 75 and the vacuum system 74.The liquid recovery unit 73, which is provided with a tank or the likecapable of accommodating the liquid 1, is connected to the gas/liquidseparator 75.

Next, an explanation will be made with reference to, for example, FIG. 1about the procedure for exposing the substrate P with the pattern of themask M by using the exposure apparatus EX as described above.

The mask M is loaded on the mask stage MST, and the substrate P isloaded on the substrate stage PST. After that, the control unit CONTdrives the liquid supply unit 11 of the liquid supply mechanism 10 tosupply, onto the substrate P, a predetermined amount of liquid 1 perunit time by the aid of the supply tube 15 and the supply nozzles 14.The control unit CONT drives the vacuum system 25 of the liquid recoverymechanism 20 in accordance with the supply of the liquid 1 by the liquidsupply mechanism 10 to recover a predetermined amount of the liquid 1per unit time by the aid of the recovery nozzles 21 and the recoverytube 24. Accordingly, the liquid immersion area AR2 of the liquid 1 isformed between the substrate P and the optical element 2 disposed at theend portion of the projection optical system PL. In this procedure, thecontrol unit CONT controls the liquid supply mechanism 10 and the liquidrecovery mechanism 20 respectively so that the liquid supply amount ontothe substrate P is substantially the same as the liquid recovery amountfrom the substrate P in order to form the liquid immersion area AR2. Thecontrol unit CONT illuminates the mask M with the exposure light beam ELby using the illumination optical system IL to project the image of thepattern of the mask M onto the substrate P via the projection opticalsystem PL and the liquid 1.

During the scanning exposure, a part of the pattern image of the mask Mis projected onto the projection area AR1. The mask M is moved at thevelocity V in the −X direction (or in the +X direction) with respect tothe projection optical system PL, in synchronization with which thesubstrate P is moved at the velocity β·V (β represents the projectionmagnification) in the +X direction (or in the −X direction) by the aidof the substrate stage PST. After the exposure is completed for one shotarea, the next shot area is moved to the scanning start position inaccordance with the stepping movement of the substrate P. The exposureprocess is successively performed thereafter for the respective shotareas in the step-and-scan manner. This embodiment is set such that theliquid 1 is allowed to flow in parallel to the direction of movement ofthe substrate P in the same direction as the direction of movement ofthe substrate P. In other words, when the scanning exposure is performedwhile moving the substrate P in the scanning direction (−X direction)indicated by the arrow Xa (see FIG. 4), the supply tube 15, the supplynozzles 14A to 14C, the recovery tube 24, and the recovery nozzles 21A,21B are used to supply and recover the liquid 1 by the liquid supplymechanism 10 and the liquid recovery mechanism 20. That is, when thesubstrate P is moved in the −X direction, then the liquid 1 is suppliedto the space between the projection optical system PL and the substrateP by the supply nozzles 14 (14A to 14C), and the liquid 1 is recoveredfrom the surface of the substrate P together with the surrounding gas bythe recovery nozzles 21 (21A, 21B). The liquid 1 is allowed to flow inthe −X direction so that the space between the substrate P and theoptical element 2 disposed at the end portion of the projection opticalsystem PL is filled with the liquid. On the other hand, when thesubstrate P is moved in the scanning direction (+X direction) indicatedby the arrow Xb (see FIG. 4) to perform the scanning exposure, thesupply tube 15′, the supply nozzles 14A′ to 14C′, the recovery tube 24′,and the recovery nozzles 21A′, 21B′ are used to supply and recover theliquid 1 by the liquid supply mechanism 10 and the liquid recoverymechanism 20. That is, when the substrate P is moved in the +Xdirection, then the liquid 1 is supplied to the space between theprojection optical system PL and the substrate P by the supply nozzles14′ (14A′ to 14C′), and the liquid 1 is recovered from the surface ofthe substrate P together with the surrounding gas by the recoverynozzles 21′ (21A′, 21B′). The liquid 1 is allowed to flow in the +Xdirection so that the space between the substrate P and the opticalelement 2 disposed at the end portion of the projection optical systemPL is filled with the liquid. In this procedure, for example, the liquid1, which is supplied through the supply nozzles 14, flows so that theliquid 1 is attracted and introduced into the space between the opticalelement 2 and the substrate P in accordance with the movement of thesubstrate P in the −X direction. Therefore, even when the supply energyof the liquid supply mechanism 10 (liquid supply unit 11) is small, theliquid 1 can be easily supplied to the space between the optical element2 and the substrate P. When the direction of the flow of the liquid 1 isswitched depending on the scanning direction, the space between theoptical element 2 and the substrate P can be filled with the liquid 1even when the substrate P is subjected to the scanning in any one of the+X direction and the −X direction. The exposure can be performed withthe high resolution and the wide depth of focus.

During the exposure process, the measurement result obtained by the flowmeter 12 provided for the liquid supply mechanism 10 and the measurementresult obtained by the flow meter 27 provided for the liquid recoverymechanism 20 are always outputted to the control unit CONT. The controlunit CONT compares the measurement result obtained by the flow meter 12,i.e., the amount of the liluid supplied onto the substrate P by theliquid supply mechanism 10 with the measurement result obtained by theflow meter 27, i.e., the amount of the liquid recovered from thesubstrate P by the liquid recovery mechanism 20 to control the valve 13of the liquid supply mechanism 10 on the basis of the result of thecomparison. Specifically, the control unit CONT determines thedifference between the liquid supply amount onto the substrate P(measurement result obtained by the flow meter 12) and the liquidrecovery amount from the substrate P (measurement result obtained by theflow meter 27) to control the valve 13 on the basis of the judgmentwhether or not the determined difference exceeds a preset allowablevalue (threshold value). In this procedure, as described above, thecontrol unit CONT controls the liquid supply mechanism 10 and the liquidrecovery mechanism 20 respectively so that the liquid supply amount ontothe substrate P is approximately the same as the liquid recovery amountfrom the substrate P. Therefore, the determined difference isapproximately zero in such a situation that the liquid supply operationby the liquid supply mechanism 10 and the liquid recovery operation bythe liquid recovery mechanism 20 are normally performed respectively.

The control unit CONT judges that any abnormality arises in the recoveryoperation of the liquid recovery mechanism 20 and the liquid 1 cannot berecovered sufficiently when the determined difference is not less thanthe allowable value, i.e., when the liquid recovery amount is extremelysmaller than the liquid supply amount. In this situation, for example,the control unit CONT judges that the abnormality such as themalfunction of the vacuum system 25 of the liquid recovery mechanism 20arises. In order to avoid the leakage of the liquid 1 which would beotherwise caused by the failure of the normal recovery of the liquid 1by the liquid recovery mechanism 20, the flow passage of the supply tube15 is blocked by operating the valve 13 of the liquid supply mechanism10 to stop the supply of the liquid 1 onto the substrate P by the liquidsupply mechanism 10. As described above, the control unit CONT comparesthe liquid amount supplied from the liquid supply mechanism 10 onto thesubstrate P with the liquid amount recovered by the liquid recoverymechanism 20 to detect the abnormality of the recovery operationperformed by the liquid recovery mechanism 20 on the basis of the resultof the comparison. When the liquid 1 is excessively supplied, and theabnormality is detected, then the control unit CONT stops the supply ofthe liquid 1 onto the substrate P. Accordingly, it is possible to avoidthe leakage of the liquid 1 to the outside of the substrate P and thesubstrate stage PST (substrate holder PH), the invasion of the liquid 1into any undesirable place, and the expansion of the damage caused bythe leakage and the invasion as described above.

When the abnormality of the recovery operation of the liquid recoverymechanism 20 is detected, the control unit CONT stops the supply of theelectric power to the electric unit for constructing the exposureapparatus EX in order to avoid the electric leakage which would beotherwise caused by the adhesion of the leaked or invaded liquid 1. Inthis arrangement, the electric unit includes, for example, the linearmotors 47, 48 for driving the substrate stage PST. The linear motors 47,48 are disposed at the positions at which the liquid 1 leaked to theoutside of the substrate P causes adhesion and invasion with ease.Therefore, the control unit CONT can avoid the electric leakage whichwould be otherwise caused by the adhesion of the liquid 1, by stoppingthe electric power supply to the linear motors 47, 48. The electric unitis not limited to the linear motors 47, 48, which also includes, forexample, the sensor (photomultiplier) which is provided on the substratestage PST to receive the exposure light beam EL radiated for thesubstrate stage PST. Further, the electric unit includes, for example,various actuators such as piezoelectric elements provided to adjust theposition of the substrate holder PH in the Z axis direction and in thedirection of inclination. When the abnormality is detected, it is alsopossible to stop the electric power supply to all of the electric unitsfor constructing the exposure apparatus EX, and it is also possible tostop the electric power supply to a part of the electric units. In thisprocedure, when the abnormality of the recovery operation of the liquidrecovery mechanism 20 is detected, for example, the control unit CONTstops the electric power supply to the electric unit (high voltage unit)including, for example, the linear motor, the piezoelectric element usedat a voltage in the vicinity of 0 to 150 V, and the photomultiplier(sensor) used at a voltage in the vicinity of 300 to 900 V. Accordingly,it is possible to avoid the occurrence of the electric leakage, and itis possible to suppress the influence on the peripheral unit which wouldbe otherwise caused by the electric leakage.

When the control unit CONT detects the abnormality of the recoveryoperation of the liquid recovery mechanism 20, for example, the controlunit CONT stops the driving of the air bearing 24 disposed to move thesubstrate stage PST in the non-contact manner with respect to the guidesurface 41A of the substrate surface plate 41. The air bearing 42includes the discharge port 42B which discharges the gas (air) againstthe upper surface (guide surface) 41A of the substrate surface plate 41,and the suction port 42A which sucks the gas from the gap between theguide surface 41A and the lower surface (bearing surface) of thesubstrate stage PST. The balance, which is brought about between therepulsive force produced by the discharge of the gas from the dischargeport 42B and the attracting force produced by the suction port 42A,maintains the constant gap between the guide surface 41A and the lowersurface of the substrate stage PST. When the control unit CONT detectsthe abnormality of the recovery operation of the liquid recoverymechanism 20, the control unit CONT stops the operation of the airbearing 42, especially the suction through the suction port 42A in orderto avoid the inflow (invasion) of the leaked liquid 1 into the suctionport 42A of the air bearing 42. Accordingly, it is possible to avoid theinflow of the liquid 1 into the vacuum system connected to the suctionport 42A, and it is possible to avoid the occurrence of theinconvenience such as the malfunction of the vacuum system which wouldbe otherwise caused by the inflow of the liquid 1.

When the projections 65 and the suction holes 66 for holding thesubstrate P are provided for any separate member, and the separatemember is attracted and held by the substrate holder PH, then thecontrol unit CONT may stop the suction through suction holes (suckingholes) for attracting and holding the separate member.

When the control unit CONT detects the abnormality of the recoveryoperation of the liquid recovery mechanism 20, the control unit CONTdrives the alarm unit K. The alarm unit K generates the alarm by using,for example, an alarm lamp, an alarm sound, and/or a display.Accordingly, for example, the operator can be informed of the occurrenceof the leakage and/or the invasion of the liquid 1 in the exposureapparatus EX.

When the abnormality of the recovery operation of the liquid recoverymechanism 20 is detected, the control unit CONT increases the liquidrecovery amount of the recovery unit 60. Specifically, the drivingamount (driving force) of the vacuum system 70 of the recovery unit 60is increased. The driving of the recovery unit 60 (vacuum system 70)brings about the vibration source. Therefore, it is desirable todecrease or stop the driving force of the recovery unit 60 during theexposure process. However, when the abnormality of the recoveryoperation of the liquid recovery mechanism 20 is detected, and anypossibility arises for the leakage of the liquid 1, then the controlunit CONT increases the driving force of the recovery unit 60.Accordingly, it is possible to avoid the leakage of the liquid 1 to theoutside of the substrate stage PST (substrate holder PH) (to at leastthe outside of the recovery port 61), and it is possible to avoid theexpansion of the leakage.

The liquid 1, which is supplied from the liquid supply mechanism 10, isrecovered by the liquid recovery mechanism 20 during the period in whichthe shot area disposed in the vicinity of the center of the substrate Pis exposed. On the other hand, as shown in FIG. 5, when the liquidimmersion area AR2 is located in the vicinity of the edge area of thesubstrate P by executing the exposure process for the edge area of thesubstrate P, the liquid 1 can be continuously retained between theprojection optical system PL and the substrate P by using the auxiliaryplate 43. However, a part of the liquid 1 outflows to the outside of theauxiliary plate 43 in some cases. The outflow liquid 1 is recovered fromthe recovery port 61 arranged with the liquid-absorbing member 62. Inthis situation, the control unit CONT starts the operation of therecovery unit 60 together with the start of the driving of the liquidsupply mechanism 10 and the liquid recovery mechanism 20 describedabove. Therefore, the liquid 1, which is recovered from the recoveryport 61, is recovered through the flow passage 63 and the tube passage68 together with the surrounding air in accordance with the suction bythe vacuum system 70. The liquid 1, which flows into the gap between thesubstrate P and the auxiliary plate 43, is recovered through the flowpassage 63 and the tube passage 68 together with the surrounding air bythe aid of the liquid recovery hole 64. In this process, the gas/liquidseparator 71 separates the gas from the liquid 1 recovered from therecovery port 61. The gas, which is separated by the gas/liquidseparator 71, is dried by the drying unit 72, and then the gas flowsinto the vacuum system 70. Accordingly, it is possible to avoid theinconvenience which would be otherwise caused such that the liquidcomponent flows into the vacuum system 70. On the other hand, theliquid, which is separated by the gas/liquid separator 71, is recoveredby the liquid recovery unit 73.

In this process, a part of the liquid 1 supplied from the liquid supplymechanism 10 is recovered by the recovery unit 60. Therefore, the liquidamount to be recovered by the liquid recovery mechanism 20 is decreased.As a result, the liquid recovery amount measured by the flow meter 27 ofthe liquid recovery mechanism 20 is decreased. In such a situation,although the liquid 1 causes no leakage, there is such a possibilitythat the control unit CONT makes any erroneous judgment that theabnormality arises in the recovery operation of the liquid recoverymechanism 20, on the basis of the result of the comparison of therespective measurement results of the flow meter 12 of the liquid supplymechanism 10 and the flow meter 27 of the liquid recovery mechanism 20.Accordingly, a flow meter, which measures the amount of the recoveredliquid, is previously provided between the gas/liquid separator 71 andthe liquid recovery unit 73 of the recovery unit 60. The control unitCONT determines the overall liquid recovery amount on the basis of themeasurement result of the flow meter of the recovery unit 60 and themeasurement result of the flow meter 27 of the liquid recovery mechanism20 to compare the determined overall liquid recovery amount with themeasurement result of the flow meter 12 of the liquid supply mechanism10. The control unit CONT judges whether or not any abnormality arisesin the liquid recovery operation of the liquid recovery mechanism 20 onthe basis of the result of the comparison. It is possible to execute thecountermeasure including, for example, the stop of the liquid supplyoperation by the liquid supply mechanism 10, the stop of the electricpower supply, and the stop of the suction operation from the suctionport, on the basis of the result of the judgment.

When the measured value of the flow meter provided for the recovery unit60 is excessively larger than a preset allowable value, the control unitCONT judges that a large amount of the liquid 1 outflows to the outsideof the substrate P. In order to avoid, for example, the leakage of theliquid 1 to the outside of the substrate stage PST (substrate holderPH), the liquid supply mechanism 10 may be stopped.

Such a situation is also assumed that the liquid 1, which outflows tothe outside of the substrate P, causes invasion through the gap betweenthe substrate P and the auxiliary plate 43 to arrive at the back surfaceside of the substrate P. There is also such a possibility that theliquid 1, which enters the back surface side of the substrate P, flowsinto the suction hole (suction port) 66 for attracting and retaining thesubstrate P. In such a situation, the suction hole 66, which is providedfor the substrate holder PH to attract and hold the substrate P, isconnected to the vacuum system 74 via the tube passage 67 and the tubepassage 69. Those provided at the intermediate positions are thegas/liquid separator 75 and the drying unit 76 for drying the gasseparated by the gas/liquid separator 75. Therefore, even if the liquid1 flows into the suction hole 66, the liquid 1, which inflows from thesuction hole 66, is recovered by the liquid recovery unit 73. It ispossible to avoid the inconvenience of the inflow of the liquidcomponent into the vacuum system 74.

When the liquid 1 causes invasion from the suction hole 66, there issuch a possibility that any inconvenience arises, for example, in theholding operation for the substrate P. Therefore, the followingprocedure is also available. That is, a flow meter is arranged betweenthe liquid recovery unit 73 and the tube passage 69 or the gas/liquidseparator 75. When the invasion of the liquid from the suction hole 66is detected by the flow meter, it is judged that any abnormal situationoccurs. It is possible to execute at least one of the stop of the liquidsupply operation, the stop of the electric power supply, and the stop ofthe suction through the suction port as described above.

In the case of an arrangement in which the gas/liquid separator 75 isnot provided for the tube passage 69 connected to the suction hole 66,the following procedure is also available. That is, when any abnormalityis detected for the recovery operation of the liquid recovery mechanism20 or the recovery unit 60, the driving of the vacuum system 74 (suctionsystem) is stopped to stop the suction through the suction hole 66 inorder to avoid the inflow of the liquid 1 into the suction hole (suctionport) 66.

As explained above, when the abnormality of the leakage or the invasionof the liquid 1 is detected, the supply of the liquid 1 onto thesubstrate P by the liquid supply mechanism 10 is stopped. Therefore, forexample, it is possible to avoid the leakage of the liquid 1, and/or itis possible to avoid the expansion of the leakage and the flooding orinundation. Even when the abnormality of the leakage or the invasion ofthe liquid 1 arises, the electric power supply is stopped for theelectric unit represented by the linear motors 47, 48 for constructingthe exposure apparatus EX. Accordingly, it is possible to avoid theoccurrence of the electric leakage and the expansion of the damagecaused by the electric leakage. The suction is stopped for the suctionport 42A of the air bearing 42 and the respective suction portscommunicated with the vacuum system, including, for example, the suctionholes 66 provided for the substrate holder PH for the purpose ofattracting and holding the substrate P. Accordingly, it is possible toavoid the occurrence of the inconvenience which would be otherwisecaused such that the liquid 1 flows into the vacuum system connected tothe suction port. Further, when the surrounding gas is recoveredtogether with the liquid from the suction ports including, for example,the recovery nozzles 21, the recovery port 61, and the suction holes 66,then the liquid and the gas, which are sucked through the suction port,is subjected to the gas/liquid separation by using the gas/liquidseparator, and the gas, which is separated by the gas/liquid separator,is further dried by the drying unit. Accordingly, it is possible toavoid the inconvenience of the inflow of the liquid component (forexample, the wet gas) into the vacuum system, and it is possible tosuppress the influence exerted on the vacuum system by the liquid. Thepresent embodiment is constructed such that the liquid is recovered fromthe suction port together with the surrounding gas. However, when therecovered liquid is separated from the gas by the gas/liquid separator,it is possible to correctly measure the amount of the recovered liquid.

The foregoing embodiment has been explained as exemplified by themalfunction (abnormal operation) of the vacuum system 25 as theabnormality of the recovery operation of the liquid recovery mechanism20. However, for example, the abnormal operation of the gas/liquidseparator 22 may be also exemplified in addition to the malfunction ofthe vacuum system 25. In other words, the occurrence of the followingsituation is assumed. Even when the liquid 1 is successfully recoveredfrom the surface of the substrate P by the aid of the recovery nozzles21, then the gas/liquid separator 22 cannot separate the gas from theliquid recovered by the recovery nozzles 21, and the liquid amountmeasured by the flow meter 27 is smaller than the predetermined value.In such a situation, the liquid component, which is allowed to flow intothe vacuum system 25, is increased, and hence the malfunction of thevacuum system 25 or the like is consequently caused. Therefore, thecontrol unit CONT stops the liquid supply operation of the liquid supplymechanism 10, and the control unit CONT stops the liquid recoveryoperation of the liquid recovery mechanism 20 (vacuum system 25).Accordingly, it is possible to avoid the leakage of the liquid 1, and itis possible to avoid the malfunction of the vacuum system 25 as well.

In the present embodiment, the control unit CONT controls the liquidsupply mechanism 10 and the liquid recovery mechanism 20 respectively sothat the liquid supply amount to the substrate P is approximately thesame as the liquid recovery amount from the substrate P. Therefore, thedetermined difference is approximately zero, and the allowable value ispreviously set to the small value corresponding thereto in the situationin which the liquid supply operation by the liquid supply mechanism 10and the liquid recovery operation by the liquid recovery mechanism 20are normally performed respectively. On the other hand, for example,when the liquid 1 to be used is highly volatile, it is assumed that theliquid 1 is volatilized on the substrate P, and the measured valueobtained by the flow meter 27 of the liquid recovery mechanism 20 issmaller than the measured value obtained by the flow meter 12 of theliquid supply mechanism 10 even in the situation in which the liquidsupply operation by the liquid supply mechanism 10 and the liquidrecovery operation by the liquid recovery mechanism 20 are normallyperformed respectively. Therefore, the control unit CONT may previouslyset the allowable value to control the valve 13 on the basis of theresult of the comparison between the preset allowable value and thedetermined difference, depending on the liquid 1 (volatility) to be usedor the environment in which the substrate P is placed.

In the embodiment described above, the liquid supply amount of theliquid supply mechanism 10 is compared with the liquid recovery amountby the liquid recovery mechanism 20 to detect the abnormality of theflow state of the liquid 1. However, the abnormality may be detected foreach of them on the basis of only the supply amount of the liquid supplymechanism 10 or only the recovery amount by the liquid recoverymechanism 20. Further, there is no limitation to the flow rate of theliquid. When any mechanical or electric abnormality is detected for theliquid supply mechanism 10 and/or the liquid recovery mechanism 20, thecontrol unit CONT can also execute the countermeasure including, forexample, the stop of the liquid supply operation by the liquid supplymechanism 10, the stop of the electric power supply, and the stop of thesuction operation from through the suction port.

In the present embodiment, the surrounding gas is also recoveredtogether with the liquid 1 from the recovery nozzles 21. Therefore, inorder to measure the liquid recovery amount more correctly, therecovered liquid and the gas are separated from each other by using thegas/liquid separator 22 to measure the amount of the separated liquid byusing the flow meter 27. Therefore, there is such a possibility that theliquid amount measured by the flow meter 27 may be varied depending onthe ability of the gas/liquid separator 22 to separate the gas and theliquid from each other as well. Accordingly, the control unit CONT canalso set the allowable value depending on the gas/liquid separator 22 tobe used (gas/liquid separating ability).

The present embodiment has been exemplified such that all of the stop ofthe liquid supply operation by the liquid supply mechanism 10, the stopof the electric power to the electric unit, and the stop of the suctionoperation from the suction port are executed when the abnormality of theliquid recovery operation of the liquid recovery mechanism 20 isdetected. However, it is also allowable to adopt such an arrangementthat at least one of them is executed.

The present embodiment is constructed such that the surrounding gas isalso recovered together with the liquid 1 from the recovery nozzles 21of the liquid recovery mechanism 20. Therefore, the gas/liquid separator22 is used to effect the separation into the liquid and the gas in orderthat the amount of the recovered liquid can be accurately measured withthe flow meter 27. However, when the liquid recovery mechanism 20 isconstructed such that only the liquid 1 is recovered from the recoverynozzles 21, the amount of the recovered liquid can be determined bymeasuring the amount of the recovered liquid, without separating theliquid and the gas from each other by using the gas/liquid separator 22.

The embodiment of the present invention is constructed such that theliquid supply operation by the liquid supply mechanism 10 is stopped,the electric power supply to the electric unit is stopped, and/or thesuction operation from the suction port is stopped when the abnormalityis detected for the recovery operation of the liquid recovery mechanism20. However, when any abnormality is detected for the positionalrelationship between the projection optical system PL and the substratestage (movable member) PST which is movable while holding the substrateP, it is also allowable to execute at least one of the stop of theliquid supply operation, the stop of the electric power supply, and thestop of the suction operation through the suction port. The abnormalpositional relationship between the substrate stage PST and theprojection optical system PL herein is such a state that the liquid 1cannot be retained under the projection optical system PL, whichincludes the abnormality of the positional relationship in at least theZ axis direction and the XY direction. In other words, even when thesupply operation of the liquid supply mechanism 10 and the recoveryoperation of the liquid recovery mechanism 20 are normal, if anyabnormality arises, for example, in the operation of the substrate stagePST, and the substrate stage PST is arranged at any position deviated inthe XY direction with respect to the desired position for the projectionoptical system PL, then a situation arises such that the liquidimmersion area AR2 of the liquid 1 cannot be formed satisfactorilybetween the projection optical system PL and the substrate P held by thesubstrate stage PST (state in which the liquid 1 cannot be retainedunder the projection optical system PL). In this case, any situationoccurs such that the liquid 1 leaks to the outside of the substrate Pand to the outside of the substrate holder PH and/or the movement mirror45 of the substrate stage PST (substrate holder PH) is inundated withthe liquid 1 or water. In such a situation, the liquid recoverymechanism 20 cannot recover the predetermined amount of the liquid 1.Therefore, the flow meter 27 of the liquid recovery mechanism 20outputs, to the control unit CONT, the measurement result of a valuesmaller than the predetermined value. The control unit CONT can detectthe abnormality of the position of the substrate stage PST at which theleakage of the liquid 1 or the like occurs, on the basis of themeasurement result of the flow meter 27. When the abnormality isdetected, the control unit CONT executes, for example, the stop of theliquid supply operation, the stop of the electric power supply, and thestop of the suction operation from the suction port.

The liquid immersion area AR2 is formed such that the distance betweenthe projection optical system PL and the substrate P is set to be apredetermined distance (about 0.1 mm to 1 mm) of such an extent that theliquid immersion area AR2 can be formed by the surface tension of theliquid 1. However, for example, when any inconvenience arises in theposition control in relation to the Z axis direction for the substratestage PST, then the distance between the projection optical system PLand the substrate P on the substrate stage PST is increased, and asituation arises such that the liquid 1 cannot be retained under theprojection optical system PL. Also in this case, for example, the liquid1 is leaked to the outside of the substrate P and the outside of thesubstrate stage PST (substrate holder PH), and the liquid recoverymechanism 20 cannot recover the predetermined amount of the liquid 1.Therefore, the flow meter 27 of the liquid recovery mechanism 20outputs, to the control unit CONT, the measurement result of a valuewhich is smaller than the predetermined value. The control unit CONT candetect the abnormality of the position of the substrate stage PST atwhich the leakage of the liquid 1 occurs, on the basis of themeasurement result obtained by the flow meter 27. When the abnormalityis detected, the control unit CONT executes, for example, the stop ofthe liquid supply operation, the stop of the electric power supply, andthe stop of the suction operation from the suction port.

In order to detect the abnormality of the positional relationship of thesubstrate stage PST with respect to the projection optical system PL,for example, the position of the substrate stage PST in the XY directionis detected by using the interferometer 46, and the abnormality of thepositional relationship can be detected on the basis of the detectionresult of the position, without using the measurement result of the flowmeter 27 of the liquid recovery mechanism 20. The control unit CONT maycompare the detection result of the position of the substrate stageobtained by the interferometer 46 with a preset allowable value. Whenthe detection result of the position of the stage obtained by theinterferometer 46 exceeds the allowable value, for example, the stop ofthe supply operation of the liquid 1 may be executed. Alternatively, theposition of the substrate stage PST in the Z axis direction may bedetected by the focus-detecting system 56 to compare the detectionresult of the position of the stage obtained by the focus-detectingsystem 56 with a preset allowable value. When the detection resultobtained by the focus-detecting system 56 exceeds the allowable value,the control unit CONT may execute, for example, the stop of the supplyoperation of the liquid 1. As described above, the control unit CONTdetects the abnormality of the positional relationship between theprojection optical system PL and the substrate stage PST on the basis ofthe detection result obtained by the substrate stage position-detectingunit including the interferometer 46 and the focus-detecting system 56.When the abnormality is detected, it is possible to execute, forexample, the stop of the liquid supply operation, the stop of theelectric power supply to the electric unit, and the stop of the suctionoperation from the suction port.

When the interferometer 46 causes any error, the control unit CONT maystop the liquid supply operation to be performed by the liquid supplymechanism 10. The error of the interferometer 46 herein includes such asituation that the measurement of the position of the substrate stagePST cannot be performed due to any cause including, for example, themalfunction of the interferometer 46 itself and the arrangement of anyforeign matter on the optical path for the measuring light beam of theinterferometer. When the interferometer 46 causes the error, the controlunit CONT cannot grasp the position of the substrate stage PST.Simultaneously, the control unit CONT cannot control the position of thesubstrate stage PST. In this situation, it is feared that anyabnormality arises in the positional relationship between the projectionoptical system PL and the substrate stage PST, and the liquid 1 causesthe leakage and the outflow. Accordingly, it is possible to avoid theinconvenience of the leakage of the liquid 1 by stopping the liquidsupply to be performed by the liquid supply mechanism 10 when theinterferometer 46 causes the error.

Similarly, when the measuring system (focus-detecting system 56 in thisembodiment), which is provided to control the position of the substratestage PST in the Z axis direction, causes any error, it is feared thatany abnormality arises in the positional relationship between theprojection optical system PL and the substrate stage PST, and the liquid1 causes the leakage and the outflow. Therefore, when thefocus-detecting system 56 causes the error, the control unit CONT canstop the liquid supply operation to be performed by the liquid supplymechanism 10.

A detecting system based on the non-optical system such as a capacitancesensor may be used for the abnormality of the positional relationship inthe Z axis direction between the substrate stage PST (substrate holderPH) and the projection optical system PL, without being limited to thefocus-detecting system 56.

The positional relationship between the image plane of the projectionoptical system PL and the surface of the substrate stage PST (substrateP) can be also managed by using an interferometer. The management of thepositional relationship between the image plane of the projectionoptical system PL and the surface of the substrate stage PST (substrateP), which is performed by using the interferometer, is disclosed, forexample, in U.S. Pat. No. 6,020,964, contents of which is incorporatedherein by reference within a range of permission of the domestic lawsand ordinances of the state designated or selected in this internationalapplication.

The embodiment described above is illustrative of the case in which theabnormality arises during the exposure operation. However, the presentinvention is also applicable equivalently in the same manner asdescribed above when the abnormality arises when the exposure for thesubstrate P is not performed.

In the embodiment described above, the supply of the liquid is stoppedwhen the abnormality is detected during the supply of the liquid.However, the start of the supply of the liquid may be stopped as wellwhen the abnormality concerning, for example, the positionalrelationship between the projection optical system PL and the substratestage PST is detected when the supply of the liquid is started.

Next, an explanation will be made about a second embodiment of theexposure apparatus EX of the present invention. In the followingexplanation, the constitutive components, which are the same as orequivalent to those of the embodiment described above, are designated bythe same reference numerals, any explanation of which will be simplifiedor omitted. In this embodiment, the leakage of the liquid 1, forexample, to the outside of the substrate P or the substrate stage PST(substrate holder PH) is optically detected by using a detectorincluding an optical fiber to execute at least one of the stop of theliquid supply operation by the liquid supply mechanism 10, the stop ofthe electric power supply to the electric unit, and the stop of thesuction operation from the suction port when the leakage or the invasionof the liquid 1 is detected.

An explanation will be made with reference to FIGS. 6 and 7 about thedetection principle of the detector for detecting the leakage of theliquid 1. The optical fiber is used as the detector in this embodiment.FIG. 6 shows a schematic arrangement illustrating a general opticalfiber. With reference to FIG. 6, the optical fiber 80′ includes a coreportion 81 through which the light is transmitted, and a clad portion 82which is provided around the core portion 81 and which has an refractiveindex smaller than that of the core portion 81. In the optical fiber80′, the light is transmitted by being confined in the core portion 81having the refractive index higher than that of the clad portion 82.

FIG. 7 shows a schematic arrangement illustrating the optical fiber 80according to the embodiment of the present invention. With reference toFIG. 7, the optical fiber 80 is such an optical fiber (clad-less fiber)that the optical fiber 80 has a core portion 81 through which the lightis transmitted, and no clad portion is provided therearound. The coreportion 81 of the optical fiber 80 has a refractive index nc which ishigher than a refractive index na of the surrounding gas (air in thisembodiment). Further, the core portion 81 has the refractive index whichis lower than a refractive index nw of the liquid (pure water in thisembodiment) 1 (na<nc<nw). Therefore, when the surrounding of the opticalfiber 80 is filled with the air, the light is transmitted while beingconfined in the core portion 81 having the refractive index nc higherthan that of the air, provided that the angle of incidence θ₀ of thelight satisfies the total reflection condition sinθ₀>na/nc. In otherwords, the light, which comes from the incoming end of the optical fiber80, outgoes from the outgoing end while the light amount is not greatlyattenuated. However, when the liquid (pure water) 1 adheres to thesurface of the optical fiber 80, then the total reflection conditionsinθ₀=na/nc cannot be satisfied at any angle of incidence at the placeto which water adheres, because of nc<nw, and the total reflection isnot caused at the interface between the liquid 1 and the optical fiber80. Accordingly, the light is leaked from the liquid adhesion portion ofthe optical fiber 80. Therefore, the light, which comes from theincoming end of the optical fiber 80, has the light amount which isdecreased when the light outgoes from the outgoing end. Accordingly,when the optical fiber 80 is installed beforehand at a predeterminedposition of the exposure apparatus EX, and the light amount is measuredat the outgoing end of the optical fiber 80, then the control unit CONTcan detect whether or not the liquid 1 adheres to the optical fiber 80,i.e., whether or not the liquid 1 is leaked. The refractive index of theair is about 1, and the refractive index of the water is about 1.4 to1.6. Therefore, it is preferable that the core portion 81 is formed of,for example, a material having a refractive index of about 1.2 (forexample, quartz or glass having a specified composition).

The amount of the liquid 1 adhered to the optical fiber 80 can be alsodetermined in accordance with the amount of attenuation of the lightallowed to outgo from the outgoing end of the optical fiber 80. That is,the amount of attenuation of the light depends on the area of theportion at which the liquid 1 adheres to the optical fiber. When a smallamount of the liquid 1 adheres to the circumference of the optical fiber80, the amount of attenuation of the light is small at the outgoing end.When a large amount of the liquid 1 adheres, the amount of attenuationis large. Therefore, it is considered that the area of the portion, atwhich the liquid 1 adheres, depends on the amount of leakage of theliquid. Accordingly, the amount of leakage of the liquid 1 can bedetermined by measuring the light amount at the outgoing end of theoptical fiber 80. Further, the measured value of the light amount at theoutgoing end of the optical fiber is compared with a plurality of presetthreshold values (reference values), and specified signals are outputtedrespectively when the measured value exceeds the respective thresholdvalues. Accordingly, the amount of leakage of the liquid 1 can bedetected in a stepwise manner.

FIG. 8 shows a side view illustrating a state in which the optical fiber80 of the detector as described above is arranged around the substratestage PST (substrate holder PH), and FIG. 9 shows a plan view of thestate. As shown in FIGS. 8 and 9, the optical fiber 80 is arranged tosurround the circumference of the substrate stage PST (substrate holderPH). A light-emitting section 83, which is capable of allowing the lightto come into the optical fiber 80, is connected to the incoming end ofthe optical fiber 80. A light-receiving section 84, which is capable ofreceiving the light transmitted through the optical fiber 80 and allowedto outgo from the outgoing end, is connected to the outgoing end of theoptical fiber 80. The control unit CONT determines the attenuation ratioof the light at the outgoing end with respect to the incoming end of theoptical fiber 80 on the basis of the amount of the light allowed to comeinto the optical fiber 80 from the light-emitting section 83 and theamount of the light received by the light-receiving section 84. Thecontrol unit CONT judges whether or not the liquid 1 adheres to theoptical fiber 80, i.e., whether or not the liquid 1 leaks to the outsideof the substrate stage PST (substrate holder PH), on the basis of thedetermined result. When it is judged that the liquid 1 leaks, thecontrol unit CONT executes, for example, the stop of the operation tosupply the liquid by the liquid supply mechanism 10, the stop of theelectric power supply to the electric unit, and the stop of the suctionoperation from the suction port.

The optical fiber 80 may be arranged on the upper surface of thesubstrate stage PST (substrate holder PH), especially around therecovery port 61. Alternatively, in order to check the inundation withthe water (inundation with the liquid) of the movement mirror 45, theoptical fiber 80 may be arranged on the movement mirror 45 or at anyportion therearound.

FIG. 10 shows an example in which the optical fibers 80 are arrangedaround the air bearings 42 provided on the lower surface of thesubstrate stage PST and around the substrate surface plate (base member)41 for movably supporting the substrate stage PST. The optical fiber 80is arbitrarily bendable. Therefore, the optical fiber 80 can be attachedin a winding manner at any arbitrary position of, for example, thesubstrate stage PST (substrate holder PH), the air bearing 42, and thesubstrate surface plate 41 at which the liquid 1 tends to leak. Theoptical fiber 80 can be freely laid out and arranged in any arbitraryform. In particular, when the optical fiber 80 is attached around theair bearing 42, then it is possible to satisfactorily detect whether ornot the liquid 1 adheres (leaks) to the vicinity of the air bearing 42,and it is possible to previously avoid the inconvenience of the inflowof the liquid 1 into the suction port 42A of the air bearing 42.

In the case of the optical fiber 80 as described above, when thedistance from the incoming end to the outgoing end is long, it issometimes difficult to specify the position at which the liquid 1adheres to the optical fiber 80, i.e., the position of the leakage ofthe liquid 1. Accordingly, a plurality of optical fibers 80 are arrangedtwo-dimensionally in a matrix form as shown in FIG. 11, and thus it ispossible to specify the position of the leakage of the liquid 1. In FIG.11, a detector 90 includes a plurality of first optical fibers 80A whichare provided and aligned in a second direction (X axis direction)perpendicular to a first direction provided that the first direction (Yaxis direction) is the longitudinal direction, and a plurality of secondoptical fibers 80B which are provided and aligned in the first directionprovided that the second direction is the longitudinal direction. Theplurality of first and second optical fibers 80A, 80B are arranged inthe matrix form (network form). Respective incoming ends of theplurality of first optical fibers 80A are collected, and the collectedportion is connected to an outgoing end of a collective fiber 85A. Anincoming end of the collective fiber 85A is connected to alight-emitting section 83A. On the other hand, respective outgoing endsof the plurality of first optical fibers 80A are connected to alight-receiving section 84A constructed of, for example, aone-dimensional CCD line sensor. Similarly, respective incoming ends ofthe plurality of second optical fibers 80B are collected, and thecollected portion is connected to an outgoing end of a collective fiber85B. An incoming end of the collective fiber 85B is connected to alight-emitting section 83B. On the other hand, respective outgoing endsof the plurality of second optical fibers 80B are connected to alight-receiving section 84B constructed of, for example, aone-dimensional CCD line sensor.

The light, which is emitted from the light-emitting section 83A, istransmitted through the collective fiber 85A, and then the light isbranched into each of the plurality of first optical fibers 80Arespectively. The lights, which come from the respective incoming endsof the first optical fibers 80A, are transmitted through the firstoptical fibers 80A. After that, the lights outgo from the outgoing ends,and the lights are received by the light-receiving section 84A. Thelight-receiving section 84A detects the amounts of the lights allowed tooutgo from the respective outgoing ends of the plurality of firstoptical fibers 80A respectively. As shown in FIG. 11, when the liquid 1adheres to the specified first optical fiber 80AL of the plurality offirst optical fibers 80A, the light amount is lowered at the outgoingend of the first optical fiber 80AL. The light-receiving result of thelight-receiving section 84A is outputted to the control unit CONT.Similarly, the light, which is emitted from the light-emitting section83B, is transmitted through the collective fiber 85B, and then the lightis branched into each of the plurality of second optical fibers 80Brespectively. The lights, which come from the respective incoming endsof the second optical fibers 80B, are transmitted through the secondoptical fibers 80B. After that, the lights outgo from the outgoing ends,and the lights are received by the light-receiving section 84B. Thelight-receiving section 84B detects the amounts of the lights allowed tooutgo from the respective outgoing ends of the plurality of secondoptical fibers 80B respectively. As shown in FIG. 11, when the liquid 1adheres to the specified second optical fiber 80BL of the plurality ofsecond optical fibers 80B, the light amount is lowered at the outgoingend of the second optical fiber 80BL. The light-receiving result of thelight-receiving section 84B is outputted to the control unit CONT. Thecontrol unit CONT can specify the fact that the leakage position of theliquid 1 (position of the adhesion of the leaked liquid 1 with respectto the detector 90) is located in the vicinity of the point ofintersection between the first optical fiber 80AL and the second opticalfiber 80BL on the basis of the respective light-receiving results of thelight-receiving sections 84A, 84B.

FIG. 12 shows an example in which the detector 90, which has the opticalfibers 80A, 80B arranged in a matrix form, is arranged for the linearmotor 47 (stator 47A) as the electromagnetic driving source for drivingthe substrate stage PST. When the detector 90 is arranged for the linearmotor 47, it is possible to specify the position of the liquid 1 whichleaks to the outside of the substrate stage PST and which adheres ontothe linear motor 47. When the position of the leaked liquid 1 isspecified, for example, it is possible to efficiently perform theoperation for removing the leaked liquid 1.

When the liquid 1 is water, and the leaked liquid (water) is removed,then the removing operation (wiping operation) is performed by usingabsolute alcohol. Accordingly, it is possible to satisfactorily removethe water. Further, the removing operation can be performed smoothly,because alcohol is volatilized immediately.

As schematically shown in FIG. 13, when the pulse light is allowed tocome from the incoming end of the optical fiber 80, it is possible tospecify the position of the liquid 1 adhered to the surface of theoptical fiber 80. When the liquid 1 adheres to the surface of theoptical fiber 80, a phenomenon occurs such that the pulse light L1,which comes from the incoming end of the optical fiber 80, is reflectedat the position of the adhesion of the liquid 1, and the reflected lightL2 is returned toward the incoming end again. Accordingly, an opticalelement such as a polarizing beam splitter is provided on the incomingside, and the reflected light is introduced with the optical elementinto a light-receiving unit to detect the reflected light. According tothe result of the detection, the distance between the incoming end andthe position of the adhesion of the liquid 1 can be determined on thebasis of the difference in time between the timing at which the pulselight L1 is allowed to come into the optical fiber 80 and the timing atwhich the reflected light L2 is received at the incoming end, and thevelocity of the light transmitted through the optical fiber 80.Accordingly, it is possible to specify the position of the adhesion ofthe liquid 1 (position of the leakage of the liquid 1). The velocity ofthe light transmitted through the optical fiber 80 is changed dependingon the material for forming the optical fiber 80 (core portion 81).Therefore, the velocity of the light can be determined on the basis ofthe material for forming the optical fiber 80.

Next, an explanation will be made about a third embodiment of theexposure apparatus EX of the present invention. In this embodiment, theleakage of the liquid 1 is optically detected by using a detectorincluding a prism (optical element). When the leakage of the liquid 1 isdetected, at least one of the stop of the liquid supply operation by theliquid supply mechanism 10, the stop of the electric power supply to theelectric unit, and the stop of the suction operation from the suctionport is executed.

An explanation will be made about the detection principle of thedetector for detecting the leakage of the liquid 1 with reference toFIGS. 14 and 15. In this embodiment, the prism is used as the detector.FIG. 14 shows a schematic arrangement of the detector 100 based on theuse of the prism. With reference to FIG. 14, the detector 100 includesthe prism 101, a light-emitting section 102 which is attached to a firstsurface 101A of the prism 101 and which emits the light with respect tothe prism 101, and a light-receiving section 103 which is attached to asecond surface 101B of the prism 101 and which receives the reflectedlight of the light emitted from the light-emitting section 102 andreflected by a third surface 101C of the prism 101. The first surface101A is approximately perpendicular to the second surface 101B.

The prism 101 has a refractive index higher than that of the surroundinggas (air in this embodiment), and the refractive index is lower thanthat of the liquid (pure water in this embodiment) 1. The refractiveindex of the prism is selected so that the light, which is emitted fromthe light-emitting section 102 to the third surface 10C, is subjected tothe total reflection on the third surface 101C when the surrounding ofthe prism 101 is filled with the air. Accordingly, the light, which isemitted from the light-emitting section 102, is received by thelight-receiving section 103 without greatly attenuating the light amountthereof.

FIG. 15 shows a state in which the liquid 1 adheres to the third surface101C of the prism 101 of the detector 100. With reference to FIG. 15,the light, which is emitted from the light-emitting section 102 to thethird surface 101C, is not subjected to the total reflection on thethird surface 101C due to the presence of the liquid 1. A part of (orall of) the light component leaks to the outside from the liquidadhesion portion of the prism 101. Therefore, the light amount of thelight component to arrive at the second surface 101B, which is includedin the light emitted from the light-emitting section 102, is attenuated.Therefore, the light-receiving section 103 can detect whether or not theliquid 1 adheres to the third surface 101C of the prism 101 on the basisof the received light amount (light information or optical information).Accordingly, the detector 100 provided with the prism 101 is previouslyinstalled at a predetermined position of the exposure apparatus EX, andthus the control unit CONT can detect whether or not the liquid 1adheres to the prism 101, i.e., whether or not the liquid 1 leaks, onthe basis of the light-receiving result of the light-receiving section103.

FIG. 16 shows a plan view illustrating an example in which the detectors100 provided with the prisms 101 are arranged around the substrate stagePST. With reference to FIG. 16, a plurality of detectors 100 areattached at predetermined intervals to the circumference of thesubstrate stage PST (substrate holder PH) in a state in which the thirdsurfaces 101C of the prisms 101 are directed upwardly. The control unitCONT determines the attenuation ratio of the outgoing light amount withrespect to the incoming light amount allowed to come into the prism 101,on the basis of the light amount obtained when the light comes into theprism 101 from the light-emitting section 102 of each of the detectors100 and the light amount received by the light-receiving section 103. Onthe basis of the determined result, the control unit CONT judges whetheror not the liquid 1 adheres to the prism 101, i.e., whether or not theliquid 1 leaks to the outside of the substrate stage PST (substrateholder PH). When it is judges that the liquid 1 leaks, the control unitCONT executes, for example, the stop of the supply operation of theliquid by the liquid supply mechanism 10, the stop of the electric powersupply to the electric unit, and the stop of the suction operation fromthe suction port.

In this embodiment, the control unit CONT can easily specify the leakageposition of the liquid 1 on the basis of the respective detectionresults of the plurality of detectors 100 and the information about theattachment positions of the detectors 100. The prism 101 can be easilyattached to any arbitrary position of the exposure apparatus EX, becausethe prism 101 is relatively small. The installation operability issatisfactory as well.

The detector 100 as described above is also applicable to a water gaugeor a water level indicator (liquid level indicator). FIG. 17schematically shows an example in which a plurality of detectors 100 areattached to the wall surface of a tank 110 capable of accommodating theliquid (water) 1 while being aligned in the height direction (Z axisdirection). The wall surface of the tank 110 is transparent. Thedetectors 100 are attached so that the third surfaces 101C of the prisms101 make contact with the wall surface of the tank 110. Thelight-receiving signal of the detector 100 (light-receiving section 103)which detects the liquid 1 in the tank 110 and which is included in theplurality of detectors 100 exhibits a value lower than that of thelight-receiving signal of the detector 100 (light-receiving section 103)which does not detect the liquid 1. Therefore, the control unit CONT candetermine the liquid level (water level) of the liquid 1 contained inthe tank 110 on the basis of the respective detection results(light-receiving results) of the plurality of detectors 100 and theinformation about the attachment positions of the plurality of detectors100 with respect to the tank 110. Accordingly, it is possible todetermine the liquid amount in the tank 110.

FIG. 18 shows a schematic arrangement illustrating an example in whichthe tank 110 provided with the detectors 100 for constructing the waterlevel indicator is applied to a part of the liquid recovery mechanism20. The liquid recovery mechanism 20 shown in FIG. 18 includes recoverynozzles 21, a vacuum system 25 which is connected via a recovery tube 24to the recovery nozzles 21, a gas/liquid separator 22 and a drying unit23 which are provided at intermediate positions of the recovery tube 24.The liquid 1, which is separated by the gas/liquid separator 22, passesthrough a second recovery tube 26, and the liquid 1 is accommodated inthe tank 110 provided with the detectors 100. In other words, thisembodiment is constructed such that the tank 110 is provided in place ofthe flow meter 27 of the liquid recovery mechanism 20 as explained withreference to FIG. 3. The detection results of the detectors 100 areoutputted to the control unit CONT. The control unit CONT determines theliquid amount recovered by the recovery nozzles 21 on the basis of thedetection results of the detectors 100. The control unit CONT can detectthe abnormality of the recovery operation of the liquid recoverymechanism 20 by comparing the liquid amount recovered with the recoverynozzles 21 and the liquid amount supplied from the liquid supplymechanism 10. The liquid recovery unit 28 is connected to the tank 110via a tube passage 28A. A valve 28B is provided at an intermediateposition of the tube passage 28A. The control unit CONT operates thevalve 28B to open the flow passage 28A when the tank 110 is filled withthe liquid 1 of an amount of not less than a predetermined amount (orperiodically). The liquid 1 contained in the tank 110 is recovered bythe liquid recovery unit 28.

In the embodiment shown in FIG. 18, the detectors 100 are attached tothe supply tube 15 and the recovery tube 24 respectively. Each of thesupply tube 15 and the recovery tube 24 is formed of a transparentmaterial. The detectors 100 are attached so that the detection surfaces100 c of the detectors 100 make tight contact with the outer surfaces ofthe tubes. The control unit CONT can detect whether or not the liquid 1flows through the supply tube 15 on the basis of the light-receivingresult of the light-receiving section 103 of the detector 100 attachedto the supply tube 15. In other words, the value of the light-receivingsignal of the light-receiving section 103 is small when the liquid 1flows through the supply tube 15 as compared with when the liquid 1 doesnot flows through the supply tube 15. Therefore, the control unit CONTcan detect whether or not the liquid 1 flows through the supply tube 15,i.e., whether or not the supply operation of the liquid supply mechanism10 is performed normally, on the basis of the light-receiving result ofthe light-receiving section 103. Similarly, the control unit CONT candetect whether or not the liquid 1 flows through the recovery tube 24,i.e., whether or not the recovery operation of the liquid recoverymechanism 20 is performed normally, on the basis of the light-receivingresult of the light-receiving section 103 of the detector 100 attachedto the recovery tube 24. As described above, the detector 100 can bealso used as a presence/absence sensor for the liquid for opticallydetecting whether or not the liquid 1 flows through the supply tube orthe recovery tube.

When the detector 100 having the prism 101 is attached, for example, tothe vicinity of the end portion of the projection optical system PL (thevicinity of the optical element 2), the detector 100 can be used todetect whether or not the space between the projection optical system PLand the substrate P is filled with the liquid 1 as well.

In the embodiments described above, the leakage of the liquid 1 and/orthe presence or absence of the liquid 1 is optically detected by usingthe optical fiber 80 or the prism 101. However, the leakage of theliquid 1 and/or the presence or absence of the liquid 1 may beelectrically detected by using a capacitance sensor.

When the liquid 1 is water, the leakage of the liquid 1 and/or thepresence or absence of the liquid 1 can be also detected electrically bya water leakage sensor which is constructed of two electric wiresseparated from each other by a predetermined spacing distance to detectthe leakage of the liquid 1 in accordance with the presence or absenceof the conduction between the two electric wires. In the embodiment ofthe present invention, water is used as the liquid 1. Therefore, it ispossible to use the water leakage sensor constructed as described above.When ultrapure water is used as the liquid 1, the water leakage sensorconstructed as described above cannot detect the presence or absence ofthe liquid 1, because ultrapure water has no conductivity. In such asituation, when an electrolyte substance is previously contained in thecoatings of the separated two electric wires, the conductivity isobtained at the point of time of the immersion of ultrapure water.Therefore, the liquid 1 as ultrapure water can be detected with thewater leakage sensor constructed as described above.

It goes without saying that the features of the respective embodimentsdescribed above can be used in combination. For example, the opticalfiber 80 can be laid out around the linear motor, and the detector 100having the prism 101 can be arranged around the substrate stage PST(substrate holder PH).

It is also allowable that the optical fiber and/or the prism are notinstalled at all of the positions described above. The optical fiberand/or the prism may be installed in the substrate stage PST and at thepositions in the vicinity of the photoelectric detector and thepiezoelectric element, if necessary.

As explained with reference to FIGS. 8 to 10, the optical fiber 80 canbe arranged to surround the circumference of the substrate stage PST andthe circumference of the substrate surface plate 41. However, as shownin a side view of FIG. 19B, the following combination is of courseallowable. That is, the first optical fiber 80C is provided around thesubstrate stage PST, and the second optical fiber 80D is provided aroundthe substrate surface plate 41. Further, the optical fiber 80 (80E) maybe also arranged in the recovery port 61 provided on the substrate stagePST. In FIG. 19, in the same manner as in the embodiment describedabove, the substrate stage PST is provided with the auxiliary plate 43which is formed to surround the circumference of the substrate P held bythe substrate holder PH, and the recovery port 61 which is provided atthe outside thereof. The auxiliary plate 43 has the flat surface (flatportion) 43A which is provided around the substrate P held by thesubstrate holder PH and which is substantially flush with the surface ofthe substrate P. The flat surface 43A is provided annularly to surroundthe circumference of the substrate P. The recovery port 61 is providedoutside the auxiliary plate 43 (flat surface 43A). The recovery port 61is an annular groove which is formed to surround the auxiliary plate 43(substrate P). In this embodiment, the liquid-absorbing member (62) isnot arranged inside the recovery port 61. As shown in a plan view ofFIG. 19A, the optical fiber 80E is arranged to extend over the entirecircumference of the recovery port 61 which is formed annularly. Whenthe optical fiber 80E for detecting the presence or absence of theliquid 1 is provided in the recovery port 61, the leaked liquid 1 can bedetected with the optical fiber 80E before the leaked liquid 1 isdiffused, even when the liquid 1 leaks from the surface of the substrateP. Therefore, the control unit CONT applies any appropriate treatmentincluding, for example, the stop of the liquid supply operation of theliquid supply mechanism 10 by using the valve 13 when the optical fiber80E detects the presence of the liquid 1. Accordingly, it is possible toavoid the diffusion of the liquid 1 and the leakage from the surface ofthe substrate stage PST. When the optical fiber 80E is arranged in therecovery port 61, the liquid-absorbing member (62) may be arranged forthe recovery port 61.

As shown in FIG. 19B, when a plurality of optical fibers 80 fordetecting the presence or absence of the liquid 1 are provided at aplurality of predetermined positions of the exposure apparatus EX(substrate stage PST) respectively, the control unit CONT may controlthe operation of the exposure apparatus EX depending on the detectionresults of the plurality of optical fibers 80. For example, the controlunit CONT selects at least one operation of the stop of the liquidsupply by the liquid supply mechanism 10 and the stop of the electricpower supply to the electric unit depending on the position of theoptical fiber 80 which has detected the liquid 1 and which is includedin the plurality of optical fibers 80.

Specifically, the control unit CONT stops the liquid supply operation ofthe liquid supply mechanism 10 when the first optical fiber 80C providedfor the substrate stage PST detects the presence of the liquid 1, andthe control unit CONT stops the electric power supply to thepredetermined electric unit when the second optical fiber 80D providedfor the substrate surface plate 41 detects the presence of the liquid 1.The predetermined electric unit herein includes, for example, the linearmotors 47, 48 for driving the substrate stage PST and the anti-vibrationunit 9 for supporting the substrate surface plate 41 in theanti-vibration manner.

When the first optical fiber 80C provided for the substrate stage PSTdetects the presence of the liquid 1, and the second optical fiber 80Dprovided for the substrate surface plate 41 does not detect the presenceof the liquid 1, then the control unit CONT judges that the leakedliquid 1 does not arrive at the linear motors 47, 48 for driving thesubstrate stage PST and the anti-vibration unit 9. In other words, thecontrol unit CONT judges that the diffusion range of the leaked liquid 1is relatively narrow. In this case, the control unit CONT executes thestop of the liquid supply operation of the liquid supply mechanism 10,but the control unit CONT continues the electric power supply to thelinear motors 47, 48 and the anti-vibration unit 9. On the other hand,when the second optical fiber 80D provided for the substrate surfaceplate 41 detects the presence of the liquid 1, the control unit CONTjudges that the leaked liquid 1 arrives at the linear motors 47, 48 andthe anti-vibration unit 9. In other words, the control unit CONT judgesthat the diffusion range of the leaked liquid 1 is relatively wide. Inthis case, the control unit CONT stops the liquid supply operation ofthe liquid supply mechanism 10, and the control unit CONT stops theelectric power supply to at least one of the linear motors 47, 48 andthe anti-vibration unit 9. When the second optical fiber 80D detects thepresence of the liquid 1, the control unit CONT executes the stop of theelectric power supply to the linear motors 47, 48 or the anti-vibrationunit 9. However, it is preferable that the control unit CONT does notexecute the stop of the electric power supply to the entire exposureapparatus EX, for the following reason. That is, if the electric powersupply to the entire exposure apparatus EX is stopped, a long period oftime is required for the restoring operation and the stabilization to beperformed thereafter.

As described above, the operation of the exposure apparatus EX iscontrolled depending on the detection results of the first optical fiber80C and the second optical fiber 80D which are provided at the mutuallydifferent positions. Accordingly, it is possible to apply theappropriate treatment or countermeasure depending on the diffusion rangeof the leaked liquid 1. Therefore, it is possible to shorten the timerequired for the restoring operation after the occurrence of the leakageof the liquid 1, and it is possible to avoid the decrease in the workingrate of the exposure apparatus EX. When the first optical fiber 80Cprovided for the substrate stage PST detects the presence of the liquid1, then the control unit CONT stops the liquid supply by the liquidsupply mechanism 10, and the control unit CONT continues the electricpower supply to the electric unit. Accordingly, the period of time,which is required for the restoring operation and the stabilization, canbe suppressed to the minimum. On the other hand, when the second opticalfiber 80D provided for the substrate surface plate 41 detects thepresence of the liquid 1, the control unit CONT stops the electric powersupply to the anti-vibration unit 9 and/or the linear motors 47, 48 fordriving the substrate stage PST. Accordingly, even when the leakedliquid is diffused over a wide range, it is possible to avoid theoccurrence of the damage such as the electric leakage and themalfunction.

The control unit CONT may control the operation of the exposureapparatus EX depending on the amount of the liquid 1 detected by theoptical fiber 80. For example, the control unit CONT selects at leastone operation of the stop of the liquid supply operation of the liquidsupply mechanism 10 and the stop of the electric power supply to theelectric unit depending on the amount of the liquid 1 detected by theoptical fiber 80.

Specifically, the control unit CONT stops the liquid supply operation ofthe liquid supply mechanism 10 when at least one of the first opticalfiber 80C and the second optical fiber 80D detects the liquid 1 of anamount of not less than a preset first reference value, and the controlunit CONT stops the electric power supply to the electric unitincluding, for example, the linear motors 47, 48 for driving thesubstrate stage PST and the anti-vibration unit 9 for supporting thesubstrate surface plate 41 in the anti-vibration manner when at leastone of the first optical fiber 80C and the second optical fiber 80Ddetects the liquid 1 of an amount of not less than a second referencevalue. In this procedure, the second reference value is larger than thefirst reference value.

When it is judged that the amount of the liquid 1, which is detected byat least any one of the first optical fiber 80C and the second opticalfiber 80D, is not less than the first reference value and less thansecond reference value, the control unit CONT judges that the amount ofthe leaked liquid 1 is relatively small. In this case, the control unitCONT executes the stop of the liquid supply operation of the liquidsupply mechanism 10, but the control unit CONT continues the electricpower supply to the linear motors 47, 48 and the anti-vibration unit 9.On the other hand, when it is judged that the amount of the liquid 1,which is detected by at least any one of the first optical fiber 80C andthe second optical fiber 80D, is not less than the second referencevalue, the control unit CONT judges that the amount of the leaked liquid1 is large. In this case, the control unit CONT stops the liquid supplyoperation of the liquid supply mechanism 10, and the control unit CONTstops the electric power supply to at least one of the linear motors 47,48 and the anti-vibration unit 9. When the optical fibers 80C, 80Ddetect the amount of the liquid 1 of not less than the second referencevalue, it is preferable that the control unit CONT executes the stop ofthe electric power supply to the linear motors 47, 48 or theanti-vibration unit 9, but the control unit CONT does not execute thestop of the electric power supply to the entire exposure apparatus EX,for the following reason. That is, if the electric power supply to theentire exposure apparatus EX is stopped, a long period of time isrequired for the restoring operation and the stabilization to beperformed thereafter.

As described above, the operation of the exposure apparatus EX can becontrolled depending on the amount of the liquid 1 detected by theoptical fiber 80 as well. Also in this case, it is possible to apply theappropriate treatment depending on the amount of the leaked liquid 1.Therefore, it is possible to shorten the period of time required for therestoring operation after the occurrence of the leakage of the liquid 1,and it is possible to avoid the decrease in the working rate of theexposure apparatus EX.

In the embodiment described above, one optical fiber 80 is arranged tosurround the circumference of each of the substrate surface plate 41 andthe substrate stage PST. However, a plurality of optical fibers can beused to surround the circumference of each of the substrate surfaceplate 41 and the substrate stage PST as well. For example, one opticalfiber 80 can be arranged for each of the four sides of the substratesurface plate 41, and the four optical fibers 80 in total can be used tosurround the circumference of the substrate surface plate 41.Accordingly, when one of the optical fibers detects the liquid 1, it ispossible to easily specify the place of the leakage of the liquid 1 byinvestigating the optical fiber which undergoes the reaction.

As described above, for example, when the positional relationshipbetween the projection optical system PL and the substrate stage PST isabnormal, the inconvenience arises such that the liquid 1 cannot beretained under the projection optical system PL, and the liquid 1 leaks.Accordingly, in order to avoid the leakage of the liquid 1, the range ofmovement of the substrate stage PST may be restricted as well. Thisprocedure will be explained with reference to FIG. 20.

In FIG. 20, the substrate stage PST has a first area LA1 as a flat areawhich includes the surface of the substrate P (or the dummy substrateDP) held by the substrate holder PH and the flat surface 43A of theauxiliary plate 43 flush with the surface of the substrate P. A secondarea LA2 as a flat area, which includes the end surface (lower surface)2 a of the projection optical system PL on the image plane side and apart of the lower surface of the plate member 2P flush with the lowersurface 2 a, is provided at the position opposed to the first area LA1.In this arrangement, the liquid 1 forms the liquid immersion area AR2while being retained between the first flat surface on the substratestage PST and the second flat surface including the end surface 2 a ofthe projection optical system PL and opposed to the first flat surface.Therefore, the area capable of retaining the liquid includes the firstarea A1 on the substrate stage PST and the second area LA2 opposed tothe first area LA1 and including the end surface 2 a of the projectionoptical system PL. The liquid 1 forms the liquid immersion area AR2while being retained between a part of the first area LA1 and the secondarea LA2. It is not necessarily indispensable that the first area LA1and the second area LA2 are flat surfaces. The surfaces may includecurved surfaces and/or irregularities provided that the liquid 1 can beretained.

In this embodiment, the liquid 1 in the liquid immersion area AR2 alsomakes contact with parts of the recovery nozzles 21 having the liquidrecovery ports 21K and the supply nozzles 14 having liquid supply ports14K arranged around the optical element 2 disposed at the end portion ofthe projection optical system PL. In other words, the second area LA2,which is capable of retaining the liquid 1, is constructed to includethe liquid contact surfaces of the supply nozzles 14 and the recoverynozzles 21.

In this embodiment, the control unit CONT restricts the movement of thesubstrate stage PST depending on the positional relationship between thefirst area LA1 and the second area LA2. Specifically, as shown in FIG.20A, when the liquid 1 is retained between the first area LA1 and thesecond area LA2, the liquid 1 can be retained until arrival at thepositional relationship between the first area LA1 and the second areaLA2 as shown in FIG. 20B. However, when the substrate stage PST is movedin the +X direction with respect to the positional relationship shown inFIG. 20B, a situation arises such that a part of the liquid immersionarea AR2 protrudes to the outside of the first area LA1, and the liquid1 cannot be retained between the first area LA1 and the second area LA2.In this situation, the control unit CONT judges that the abnormalityarises in the positional relationship between the first area LA1 and thesecond area LA2, and the control unit CONT restricts the movement of thesubstrate stage PST. Specifically, the control unit CONT stops themovement of the substrate stage PST. Accordingly, it is possible toavoid the inconvenience such as the outflow of the liquid 1.

In this procedure, the control unit CONT can judge whether or not theabnormality arises in the positional relationship between the first areaLA1 and the second area LA2 according to the measurement result of theinterferometer 46. The control unit CONT detects the position of thesubstrate stage PST in the XY direction by the interferometer 46. Thecontrol unit CONT determines the position information of the first areaLA1 with respect to the second area LA2, i.e., the positionalrelationship between the first area LA1 and the second area LA2 on thebasis of the position detection result. The information about therespective sizes of the first area LA1 and the second area LA2 ispreviously stored in the control unit CONT. The information about thesize of the liquid immersion area AR2 to be formed between the firstarea LA1 and the second area LA2 is also previously determined, forexample, by an experiment or simulation, which is stored in the controlunit CONT. Further, the abnormal value in relation to the positionalrelationship between the first area LA1 and the second area LA2 ispreviously determined for the control unit CONT, and the abnormal valueis stored in the control unit CONT. In this procedure, the abnormalvalue is a value (relative distance) in which a positional relationshipthat the liquid 1 cannot be retained between the first area LA1 and thesecond area LA2. When the first area LA1 exceeds the abnormal value withrespect to the second area LA2, it is impossible to retain the liquid 1between the first area LA1 and the second area LA2.

When the position of the first area LA1 with respect to the second areaLA2 exceeds the abnormal value on the basis of the measurement result ofthe interferometer 46, the control unit CONT restricts (stops) themovement of the substrate stage PST. Accordingly, it is possible toavoid the inconvenience such as the outflow of the liquid 1.

When the position of the first area LA1 with respect to the second areaLA2 exceeds the abnormal value on the basis of the measurement result ofthe interferometer 46, the control unit CONT may change the direction ofthe movement of the substrate stage PST in place of the stop of themovement of the substrate stage PST. Specifically, with reference toFIG. 20, when the second area LA2 is in the abnormal positionalrelationship with respect to the first area LA1 due to the movement ofthe substrate stage PST in the +X direction, the control unit CONT movesthe substrate stage PST, for example, in the −X direction. Accordingly,it is also possible to avoid the inconvenience such as the outflow ofthe liquid 1.

When the abnormality arises in the positional relationship between thefirst area LA1 and the second area LA2, and the position of the firstarea LA1 with respect to the second area LA2 exceeds the abnormal value,then the control unit CONT may restrict the operation of the liquidsupply mechanism (10). Specifically, when the abnormality arises in thepositional relationship between the first area LA1 and the second areaLA2, the control unit CONT stops the liquid supply operation by theliquid supply mechanism (10). Accordingly, it is also possible to avoidthe inconvenience such as the outflow of the liquid 1. Alternatively,when the second area LA2 is in the abnormal positional relationship withrespect to the first area LA1, the control unit CONT reduces the liquidsupply amount (liquid supply amount per unit time) by the liquid supplymechanism (10). Further alternatively, when the abnormality arises inthe positional relationship between the first area LA1 and the secondarea LA2, then the control unit CONT may stop the electric power supplyto the linear motors (47, 48) and the anti-vibration unit (9), or thecontrol unit CONT may stop the suction through the suction port (42A).

On the other hand, the liquid 1 is not retained between the first areaLA1 and the second area LA2, for example, after stopping the supply ofthe liquid by the liquid supply mechanism (10) after the completion ofthe liquid immersion exposure for the substrate P and recovering theliquid 1 from the surface of the substrate P (substrate stage PST) bythe liquid recovery mechanism (20). In such a situation, the controlunit CONT releases the substrate stage PST from the restriction of themovement. In other words, the control unit CONT restricts the movementrange of the substrate stage PST to be the first range in which theliquid 1 can be retained between the first area LA1 and the second areaLA2 during the period in which the liquid supply mechanism (10) suppliesthe liquid 1, while the control unit CONT restricts the movement rangeof the substrate stage PST to be the second range which is wider thanthe first range during the period in which the liquid supply mechanism(10) stops the supply of the liquid 1. That is, the control unit CONTrestricts the movement range of the substrate stage PST to be the firstrange when the liquid 1 is retained between the projection opticalsystem PL and the substrate stage PST (substrate P), while the controlunit CONT permits the movement of the substrate stage PST within thesecond range which is wider than the first range when the liquid 1 isnot retained between the projection optical system PL and the substratestage PST (substrate P). Accordingly, the liquid 1 can be satisfactorilyretained continuously between the projection optical system PL and thesubstrate stage PST (substrate P), for example, during the exposure forthe substrate P. It is possible to smoothly perform the predeterminedoperation including, for example, the operation in which the substratestage PST is moved to the load/unload position for the substrate P asthe operation to be performed thereafter.

FIG. 21 shows another embodiment of the present invention, wherein FIG.21A shows a side view, and FIG. 21B shows a plan view in which thesubstrate stage is viewed from an upward position. With reference toFIG. 21A, a nozzle member 18, which has liquid supply ports 14K andliquid recovery ports 21K, is provided around the optical element 2 ofthe projection optical system PL. In this embodiment, the nozzle member18 is an annular member which is provided to surround the side surfaceof the optical element 2 over the substrate P (substrate stage PST). Thegap is provided between the nozzle member 18 and the optical element 2.The nozzle member 18 is supported by a predetermined support mechanismso that the nozzle member 18 is isolated from the vibration of theoptical element 2.

The nozzle member 18 is provided with the liquid supply ports 14K whichare provided over the substrate P (substrate stage PST) and which arearranged to be opposed to the surface of the substrate P. In thisembodiment, the nozzle member 18 has the two liquid supply ports 14K.The liquid supply ports 14K are provided on the lower surface 18 a ofthe nozzle member 18.

Further, the nozzle member 18 is provided with the liquid recovery ports21K which are provided over the substrate P (substrate stage PST) andwhich are arranged to be opposed to the surface of the substrate P. Inthis embodiment, the nozzle member 18 has the two liquid recovery ports21K. The liquid recovery ports 21K are provided on the lower surface 18a of the nozzle member 18.

The liquid supply ports 14K, 14K are provided at the respectivepositions on the both sides in the X axis direction with the projectionarea AR1 of the projection optical system PL intervening therebetween.The liquid recovery ports 21K, 21K are provided outside the liquidsupply ports 14K, 14K with respect to the projection area AR1 of theprojection optical system PL. In this embodiment, the projection areaAR1 of the projection optical system PL is set to have a rectangularshape as viewed in a plan view in which the Y axis direction is thelongitudinal direction and the X axis direction is the transversedirection.

The lower surface (surface directed toward the substrate P) 18 a of thenozzle member 18 is a substantially flat surface. The lower surface(liquid contact surface) 2 a of the optical element 2 is also a flatsurface. The lower surface 18 a of the nozzle member 18 is substantiallyflush with the lower surface 2 a of the optical element 2. Accordingly,the liquid immersion area AR2 can be satisfactorily formed over a widerange. The second area LA2, in which the liquid 1 can be retained, isthe area disposed inside the recovery ports 21K, of the lower surface 2a of the optical element 2 and the lower surface 18 a of the nozzlemember 18.

A recess 55 is provided on the substrate stage PST. The substrate holderPH is arranged in the recess 55. The upper surface 57 other than therecess 55 of the substrate stage PST is the flat surface (flat portion)to have approximately the same height as that of (to be flush with) thesurface of the substrate P held by the substrate holder PH. The firstarea LA1, in which the liquid 1 can be retained, is the area whichincludes the upper surface 57 and the surface of the substrate P.

As shown in FIG. 21B, the movement mirrors 45 are arranged at the twoedges of the substrate stage PST which has a rectangular shape as viewedin the plan view, the two edges being perpendicular to one another. Areference member 300 is arranged at a predetermined position outside thesubstrate P on the substrate stage PST. A reference mark PFM to bedetected by an unillustrated substrate alignment system and a referencemark MFM to be detected by a mask alignment system are provided in apredetermined positional relationship on the reference member 300. Inthis embodiment, the FIA (field image alignment) system is adopted forthe substrate alignment system as disclosed, for example, in JapanesePatent Application Laid-open No. 4-65603, in which the illuminationlight beam such as the white light is radiated from a halogen lamp whileallowing the substrate stage PST to stand still, and an obtained imageof a mark is photographed in a predetermined image pickup field by animage pickup element to measure the position of the mark by means of theimage processing. In this embodiment, the VRA (visual reticle alignment)system is adopted for the mask alignment system as disclosed, forexample, in Japanese Patent Application Laid-open No. 7-176468 in whichthe light beam is radiated onto a mark, and the image data of the markphotographed by a CCD camera or the like is subjected to the imageprocessing to detect the position of the mark. The upper surface 301A ofthe reference member 300 is a substantially flat surface, which isprovided to have approximately the same height as those of (to be flushwith) the upper surface 57 of the substrate stage PST and the surface ofthe substrate P held by the substrate stage PST. The upper surface 301Aof the reference member 300 can also serve as the reference surface forthe focus-detecting system 56.

The substrate alignment system also detects alignment marks AM formed onthe substrate P. As shown in FIG. 21B, a plurality of shot areas S1 toS24 are formed on the substrate P. The plurality of alignment marks AMare provided on the substrate P corresponding to the plurality of shotareas S1 to S24.

An uneven illuminance sensor 400 as a measuring sensor, which isdisclosed, for example, in Japanese Patent Application Laid-open No.57-117238, is arranged at a predetermined position outside the substrateP on the substrate stage PST. The uneven illuminance sensor 400 isprovided with an upper plate 401 which is rectangular as viewed in aplan view. The upper surface 401A of the upper plate 401 is asubstantially flat surface, which is provided to have substantially thesame height as those of (to be flush with) the surface of the substrateP held by the substrate stage PST and the upper surface 57 of thesubstrate stage PST. A pinhole portion 470, through which the light istransmissive, is provided through the upper surface 401A of the upperplate 401. Portions of the upper surface 401A other than the pinholeportion 470 are coated with a light-shielding material such as chromium.

A spatial image-measuring sensor 500 as a measuring sensor, which isdisclosed, for example, in Japanese Patent Application Laid-open No.2002-14005, is provided at a predetermined position outside thesubstrate P on the substrate stage PST. The spatial image-measuringsensor 500 is provided with an upper plate 501 which is rectangular asviewed in a plan view. The upper surface 501A of the upper plate 501 isa substantially flat surface, which is provided to have substantiallythe same height as those of (to be flush with) the surface of thesubstrate P held by the substrate stage PST and the upper surface 57 ofthe substrate stage PST. A slit portion 570, through which the light istransmissive, is provided through the upper surface 501A of the upperplate 501. Portions of the upper surface 501A other than the slitportion 570 are coated with a light-shielding material such as chromium.

A radiation amount sensor (illuminance sensor) 600, which is disclosed,for example, in Japanese Patent Application Laid-open No. 11-16816, isalso provided on the substrate stage PST. The upper surface 601A of theupper plate 601 of the radiation amount sensor 600 is provided to havesubstantially the same height as those of (to be flush with) the surfaceof the substrate P held by the substrate stage PST and the upper surface57 of the substrate stage PST.

A gutter member 89 is provided on the side surfaces of the substratestage PST to surround the substrate stage PST. The gutter member 89 iscapable of recovering (capable of retaining) the liquid 1 leaked fromthe surface of the substrate P and the surface of the substrate stagePST, and is provided outside the upper surface (flat surface) 57 of thesubstrate stage PST. An optical fiber 80, which is capable of detectingthe presence or absence of the liquid 1, is arranged in the guttermember 89. When the optical fiber 80 in the gutter member 89 detects thepresence of the liquid 1, the control unit CONT applies the appropriatetreatment such as the stop of the liquid supply operation of the liquidsupply mechanism (10) in the same manner as in the embodiment describedabove.

In this embodiment, the liquid immersion area AR2 is formed on thesubstrate P when the substrate P is exposed as a matter of course, andthe liquid immersion area AR2 is formed on the upper plates 301, 401,501, 601 respectively when the reference mark MFM of, for example, thereference member 300 is measured and when the measuring process isperformed by using the sensors 400, 500, 600. The measuring process isperformed via the liquid 1. For example, when the reference mark MFM onthe reference member 300 is measured via the liquid 1, then the area ofthe first area LA1 including the upper surface 301A of the referencemember 300 is opposed to the second area LA2, and the space between apart of the first area LA1 and the second area LA2 is filled with theliquid 1. When the measuring process is performed via the liquid 1 byusing the uneven illuminance sensor 400, then the area of the first areaLA1 including the upper surface 401A of the upper plate 401 is opposedto the second area LA2, and the space between a part of the first areaLA1 and the second area LA2 is filled with the liquid 1. Similarly, whenthe measuring process is performed via the liquid 1 by using the sensors500, 600, then the area of the first area LA1 including the uppersurfaces 501A, 601A of the upper plates 501, 601 is opposed to thesecond area LA2, and the space between a part of the first area LA1 andthe second area LA2 is filled with the liquid 1.

The control unit CONT restricts the movement range of the substratestage PST to be the first range SR1 shown in FIG. 21B during the periodin which the liquid supply mechanism (10) supplies the liquid 1 to formthe liquid immersion area AR2 on the substrate stage PST (on the firstarea LA1). With reference to FIG. 21B, the reference numeral LA2 aindicates the position obtained when the second area LA2 is arrangedmost closely to the +Y side and the −X side in the first area LA1 withinthe range in which the liquid 1 can be retained. In FIG. 21B, theexplanation is made assuming that the optical axis AX of the projectionoptical system PL (second area LA2) is moved with respect to thesubstrate stage PST (first area LA1) in order to simplify theexplanation. Similarly, the reference numeral LA2 b indicates theposition obtained when the second area LA2 is arranged most closely tothe +Y side and the +X side in the first area LA1. The reference numeralLA2 c indicates the position obtained when the second area LA2 isarranged most closely to the −Y side and the +X side in the first areaLA1. The reference numeral LA2 d indicates the position obtained whenthe second area LA2 is arranged most closely to the −Y side and the −Xside in the first area LA1.

The inner area, which is obtained by connecting the respective centers(positions of the optical axis AX of the projection optical system PL inthis case) of the respective second areas LA2 a to LA2 d, is the firstrange SR1. As described above, the movement range of the substrate stagePST is restricted to the first range SR1 during the period in which theliquid supply mechanism (10) supplies the liquid 1. Accordingly, theliquid 1 can be always retained between the first area LA1 and thesecond area LA2. It is possible to avoid the inconvenience such as theleakage of the liquid 1.

On the other hand, the control unit CONT restricts the movement range ofthe substrate stage PST to the second range SR2 which is wider than thefirst range SR1 during the period in which the liquid supply mechanism(10) does not supply the liquid 1. In this arrangement, the first rangeSR1 is included in the second range SR2. As described above, themovement range of the substrate stage PST is restricted to the secondrange SR2 which is wider than the first range SR1 during the period inwhich the liquid supply mechanism (10) stops the supply of the liquid 1.Accordingly, it is possible to smoothly perform the predeterminedoperation such as the operation for allowing the substrate stage PST tobe moved to the load/unload position for the substrate P.

As described above, the respective embodiments of the present inventionhave been specifically explained. According to the present invention,when the abnormality is detected by the control unit provided for theexposure apparatus, the control unit controls the appropriate mechanismand the unit of the exposure apparatus to previously avoid, for example,the electric leakage caused by the water leakage or the like and thesuction of the leak water. FIG. 23 shows a block diagram collectivelyillustrating the relationship among the detecting section for detectingthe abnormality, the control unit, and the control objective section tobe controlled by the control unit. The control unit of the exposureapparatus is connected to the various detecting systems including, forexample, the various detecting units provided in the exposure apparatussuch as the supply side/recovery side flow meter for detecting theabnormality of the situation (liquid flow) on the basis of the supplyside flow meter or the recovery side flow meter singly or the differencein the flow rate therebetween, the stage interferometer for detectingthe stage position abnormality (or the occurrence of the water leakagecaused thereby) by measuring the stage position of the substrate stage,the focus-detecting system for detecting the stage position abnormality(or the occurrence of the water leakage caused thereby) by measuring thefocus situation of the substrate stage, the leakage detector 700, 701for detecting the water leakage (abnormality) adhered to the opticalfiber and/or the prism provided for the substrate stage and/or the baseplate, and the water level indicator for detecting the abnormality ofthe recovery amount from the water level of the recovery tank. Thecontrol unit can receive the abnormal signal from the detecting systemsas described above. In this procedure, the control unit can judgewhether the signal is the normal signal or the abnormal signal bycomparing the predetermined reference signal with the signal receivedfrom each of the detectors.

The control unit of the exposure apparatus is also connected to thevarious related units disposed outside the exposure apparatus,including, for example, the liluid (pure water) producing unit, theliquid (pure water) temperature adjusting unit, the developing unit, andthe substrate transport unit. The control unit can receive the signalnotifying the abnormality of the related units as described above. Thecontrol unit of the exposure apparatus can also receive the signalnotifying the abnormality of the factory in which the exposure apparatusis installed. The abnormality of the factory or the like in which theexposure apparatus is installed includes, for example, the abnormalityof the clean room in which the exposure apparatus is arranged, theabnormality of the capacity of the electric power and the pure water tobe supplied to the exposure apparatus, the earthquake, and the fire. Thecontrol unit may judge whether or not the signal is the normal signal orthe abnormal signal by comparing the predetermined reference signal witheach of the signals received from the respective related units.

Further, as explained in the respective embodiments described above, thecontrol unit of the exposure apparatus is connected to the controlobjective units such as the various components including, for example,the liquid supply mechanism, the liquid recovery mechanism, the stageunit, especially the stage air bearing, the stage linear motor, thesubstrate holder-attracting system, the sensor such as thephotomultiplier, the anti-vibration unit, and the actuator. The controlunit can receive the signals notifying the abnormality of the respectivecomponents. When the sensor for detecting the earthquake is provided,the control unit can also receive the abnormal signal from theearthquake sensor. When the water quality sensor for measuring thequality of the liquid 1 (temperature, dissolved oxygen concentration,and ratio of impurity such as organic matter) is provided, the controlunit can also receive the abnormal signal from the water quality sensor.

The control operation of the control unit will be briefly explained withreference to FIG. 24. The control unit receives the signal to indicatethe abnormality, for example, from the detecting system disposed insidethe exposure apparatus or the related units 1 to 4 disposed outside theexposure apparatus. The signal, which indicates the abnormality, is, forexample, the signal which exerts any influence on the flow of the liluidsupplied (and recovered) for the liquid immersion exposure. In thisprocedure, the control unit may compare the received signal with thereference signal to judge that the received signal is the abnormalsignal. Subsequently, the control unit specifies, from the abnormalsignal, the portion at which the abnormality arises. In this situation,the control unit may generate the alarm by the alarm unit. The controlunit judges any unit or device to be controlled depending on the portionat which the abnormality arises. The control unit feeds the controlsignal to the unit to make the countermeasure against the abnormalsituation. For example, when the liquid leakage is detected by thedetector 1 (for example, the optical fiber) provided for the substratestage, the control unit can stop the liquid supply by the liquid supplymechanism, the movement of the stage by the stage control system, thesuction by the stage air bearing and the substrate holder-attractingsystem, and the electric power supply to the stage linear motor, thesubstrate holder-attracting system, the sensor, the anti-vibration unit,and the actuator respectively depending on the detection signal, whilethe control unit can continue only the liquid recovery by the liquidrecovery mechanism. The control unit judges any certain unit for whichthe operation is to be stopped, depending on the place at which theliquid leaks and the degree thereof (magnitude of the signal). Dependingon the magnitude of the detection signal, only the operation of theliquid supply mechanism may be stopped, while the electric units such asthe stage linear motor and the sensor are operated as they are.

As described above, pure water is used as the liquid 1 in theembodiments of the present invention. Pure water is advantageous in thatpure water is available in a large amount with ease, for example, in thesemiconductor production factory, and pure water exerts no harmfulinfluence, for example, on the optical element (lens) and thephotoresist on the substrate P. Further, pure water exerts no harmfulinfluence on the environment, and the content of impurity is extremelylow. Therefore, it is also expected to obtain the function to wash thesurface of the substrate P and the surface of the optical elementprovided at the end surface of the projection optical system PL.

It is approved that the refractive index n of pure water (water) withrespect to the exposure light beam EL having a wavelength of about 193nm is approximately in an extent of 1.44. When the ArF excimer laserbeam (wavelength: 193 nm) is used as the light source of the exposurelight beam EL, then the wavelength is shortened on the substrate P by1/n, i.e., to about 134 nm, and a high resolution is obtained. Further,the depth of focus is magnified about n times, i.e., about 1.44 times ascompared with the value obtained in the air. Therefore, when it isenough to secure an approximately equivalent depth of focus as comparedwith the case of the use in the air, it is possible to further increasethe numerical aperture of the projection optical system PL. Also in thisviewpoint, the resolution is improved.

In the embodiments of the present invention, the optical element 2 isattached to the end portion of the projection optical system PL.However, the optical element, which is attached to the end portion ofthe projection optical system PL, may be an optical plate which isusable to adjust the optical characteristics of the projection opticalsystem PL, for example, the aberration (for example, sphericalaberration and comatic aberration). Alternatively, the optical elementmay be a parallel plane plate through which the exposure light beam ELis transmissive. When the optical element, which makes contact with theliquid 1, is the parallel plane plate which is cheaper than the lens, itis enough that the parallel plane plate is merely exchanged immediatelybefore supplying the liquid 1 even when any substance (for example, anysilicon-based organic matter), which deteriorates the transmittance ofthe projection optical system PL, the illuminance of the exposure lightbeam EL on the substrate P, and the uniformity of the illuminancedistribution, is adhered to the parallel plane plate, for example,during the transport, the assembling, and/or the adjustment of theexposure apparatus EX. An advantage is obtained such that the exchangecost is lowered as compared with the case in which the optical elementto make contact with the liquid 1 is the lens. That is, the surface ofthe optical element to make contact with the liquid 1 is dirtied, forexample, due to the adhesion of scattered particles generated from theresist by being irradiated with the exposure light beam EL or anyimpurity contained in the liquid 1. Therefore, it is necessary toperiodically exchange the optical element. However, when the opticalelement is the cheap parallel plane plate, then the cost of the exchangepart is low as compared with the lens, and it is possible to shorten thetime required for the exchange. Thus, it is possible to suppress theincrease in the maintenance cost (running cost) and the decrease in thethroughput.

The liquid 1 is water in the embodiments of the present invention.However, the liquid 1 may be any liquid other than water. For example,when the light source of the exposure light beam EL is the F2 laser, theF₂ laser beam is not transmitted through water. Therefore, in this case,liquids preferably usable as the liquid 1 may include, for example, thefluorine-based liquid such as fluorine-based oil and perfluoropolyether(PFPE) through which the F2 laser beam is transmissive. Alternatively,other than the above, it is also possible to use, as the liquid 1,liquids (for example, cedar oil) which have the transmittance withrespect to the exposure light beam EL, which have the refractive indexas high as possible, and which are stable against the photoresist coatedon the surface of the substrate P and the projection optical system PL.

In the respective embodiments described above, the shape of the nozzleis not specifically limited. For example, two pairs of the nozzles maybe used to supply or recover the liquid 1 for the long side of theprojection area AR1. In this arrangement, the supply nozzles and therecovery nozzles may be arranged while being aligned vertically in orderthat the liquid 1 can be supplied and recovered in any one of thedirections of the +X direction and the −X direction.

The substrate P, which is usable in the respective embodiments describedabove, is not limited to the semiconductor wafer for producing thesemiconductor device. The applicable substrates include, for example,the glass substrate for the display device, the ceramic wafer for thethin film magnetic head, and the master plate (synthetic quartz, siliconwafer) for the mask or the reticle to be used for the exposureapparatus.

In the embodiments described above, the exposure apparatus is adopted,in which the space between the projection optical system PL and thesubstrate P is locally filled with the liquid. However, the presentinvention is also applicable to a liquid immersion exposure apparatus inwhich a stage holding a substrate as an exposure objective is moved in aliquid tank, and a liquid immersion exposure apparatus in which a liquidtank having a predetermined depth is formed on a stage and a substrateis held therein. The structure and the exposure operation of the liquidimmersion exposure apparatus in which the stage holding the substrate asthe exposure objective is moved in the liquid tank are described indetail, for example, in Japanese Patent Application Laid-open No.6-124873. The structure and the exposure operation of the liquidimmersion exposure apparatus in which the liquid tank having thepredetermined depth is formed on the stage and the substrate is heldtherein are described in detail, for example, in Japanese PatentApplication Laid-open No. 10-303114 and U.S. Pat. No. 5,825,043,contents of which are incorporated herein by reference respectivelywithin a range of permission of the domestic laws and ordinances of thestate designated or selected in this international application.

As for the exposure apparatus EX, the present invention is alsoapplicable to the scanning type exposure apparatus (scanning stepper)based on the step-and-scan system for performing the scanning exposurefor the pattern of the mask M by synchronously moving the mask M and thesubstrate P as well as the projection exposure apparatus (stepper) basedon the step-and-repeat system for performing the full field exposure forthe pattern of the mask M in a state in which the mask M and thesubstrate P are allowed to stand still, while successively step-movingthe substrate P. The present invention is also applicable to theexposure apparatus based on the step-and-stitch system in which at leasttwo patterns are partially overlaid and transferred on the substrate P.

The present invention is also applicable to a twin-stage type exposureapparatus which is provided with two stages capable of movingindependently in the XY direction while separately placing processingobjective substrates such as wafers. The structure and the exposureoperation of the twin-stage type exposure apparatus are disclosed, forexample, in Japanese Patent Application Laid-open Nos. 10-163099 and10-214783 (corresponding to U.S. Pat. Nos. 6,341,007, 6,400,441,6,549,269, and 6,590,634), Published Japanese Translation of PCTInternational Publication for Patent Application No. 2000-505958(corresponding to U.S. Pat. No. 5,969,441), and U.S. Pat. No. 6,208,407,contents of which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

As disclosed in Japanese Patent Application Laid-open No. 11-135400, thepresent invention is also applicable to the exposure apparatus which isprovided with a substrate stage for holding the substrate P, and ameasuring stage provided with, for example, various measuring membersand sensors. In this case, the liquid can be also retained between theprojection optical system and the upper surface of the measuring stage.The countermeasure such as the water leakage detector as described abovecan be also applied to the measuring stage.

As for the type of the exposure apparatus EX, the present invention isnot limited to the exposure apparatus for the semiconductor deviceproduction for exposing the substrate P with the semiconductor devicepattern. The present invention is also widely applicable, for example,to the exposure apparatus for producing the liquid crystal displaydevice or for producing the display as well as the exposure apparatusfor producing, for example, the thin film magnetic head, the imagepickup device (CCD), the reticle, or the mask.

When the linear motor is used for the substrate stage PST and/or themask stage MST, it is allowable to use any one of those of the airfloating type based on the use of the air bearing and those of themagnetic floating type based on the use of the Lorentz's force or thereactance force. Each of the stages PST, MST may be either of the typein which the movement is effected along the guide or of the guidelesstype in which no guide is provided. An example of the use of the linearmotor for the stage is disclosed in U.S. Pat. Nos. 5,623,853 and5,528,118, contents of which are incorporated herein by referencerespectively within a range of permission of the domestic laws andordinances of the state designated or selected in this internationalapplication.

As for the driving mechanism for each of the stages PST, MST, it is alsoallowable to use a plane motor in which a magnet unit provided withtwo-dimensionally arranged magnets and an armature unit provided withtwo-dimensionally arranged coils are opposed to one another, and each ofthe stages PST, MST is driven by the electromagnetic force. In thisarrangement, any one of the magnet unit and the armature unit isconnected to the stage PST, MST, and the other of the magnet unit andthe armature unit is provided on the side of the movable surface of thestage PST, MST.

The reaction force, which is generated in accordance with the movementof the substrate stage PST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,528,118 (Japanese Patent Application Laid-open No. 8-166475), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

The reaction force, which is generated in accordance with the movementof the mask stage MST, may be mechanically released to the floor(ground) by using a frame member so that the reaction force is nottransmitted to the projection optical system PL. The method for handlingthe reaction force is disclosed in detail, for example, in U.S. Pat. No.5,874,820 (Japanese Patent Application Laid-open No. 8-330224), contentsof which are incorporated herein by reference within a range ofpermission of the domestic laws and ordinances of the state designatedor selected in this international application.

The exposure apparatus EX according to the embodiment of the presentinvention is produced by assembling the various subsystems including therespective constitutive elements as defined in claims so that thepredetermined mechanical accuracy, the electric accuracy, and theoptical accuracy are maintained. In order to secure the variousaccuracies, those performed before and after the assembling include theadjustment for achieving the optical accuracy for the various opticalsystems, the adjustment for achieving the mechanical accuracy for thevarious mechanical systems, and the adjustment for achieving theelectric accuracy for the various electric systems. The steps ofassembling the various subsystems into the exposure apparatus include,for example, the mechanical connection, the wiring connection of theelectric circuits, and the piping connection of the air pressurecircuits in correlation with the various subsystems. It goes withoutsaying that the steps of assembling the respective individual subsystemsare performed before performing the steps of assembling the varioussubsystems into the exposure apparatus. When the steps of assembling thevarious subsystems into the exposure apparatus are completed, theoverall adjustment is performed to secure the various accuracies as theentire exposure apparatus. It is desirable that the exposure apparatusis produced in a clean room in which, for example, the temperature andthe cleanness are managed.

As shown in FIG. 22, the microdevice such as the semiconductor device isproduced by performing, for example, a step 201 of designing thefunction and the performance of the microdevice, a step 202 ofmanufacturing a mask (reticle) based on the designing step, a step 203of producing a substrate as a base material for the device, a substrateprocessing step 204 of exposing the substrate with a pattern of thereticle by using the exposure apparatus EX of the embodiment describedabove, a step 205 of assembling the device (including a dicing step, abonding step, and a packaging step), and an inspection step 206.

According to the present invention, the abnormality of the internal unitof the exposure apparatus or the related unit disposed outside theexposure apparatus, which affects the liquid immersion exposure, can bedetected to suppress or reduce the influence exerted on the peripheralunit, the members, and/or the exposure operation due to the leakageand/or the invasion of the liquid for the exposure. Therefore, it ispossible to maintain the satisfactory state of the expensive exposureapparatus, and it is possible to accurately perform the liquid immersionexposure process. Accordingly, it is possible to produce the devicehaving the desired performance.

1. A lithographic projection apparatus, comprising: a projection system arranged to transfer a pattern from a patterning device onto a substrate; and a liquid supply system configured to at least partially fill a space between the projection system and the substrate, the liquid supply system comprising a detector configured to detect an oversupply of liquid to the space and a controller configured to cut off supply of liquid in the event of a detected overflow. 